U.S. patent application number 14/170300 was filed with the patent office on 2014-08-21 for inkjet recording method and inkjet recording device.
This patent application is currently assigned to FUJIFILM Corporation. The applicant listed for this patent is FUJIFILM Corporation. Invention is credited to Toshiyuki MAKUTA.
Application Number | 20140232790 14/170300 |
Document ID | / |
Family ID | 50101774 |
Filed Date | 2014-08-21 |
United States Patent
Application |
20140232790 |
Kind Code |
A1 |
MAKUTA; Toshiyuki |
August 21, 2014 |
INKJET RECORDING METHOD AND INKJET RECORDING DEVICE
Abstract
An inkjet recording method includes a step of forming an image
by imparting an actinic ray curable ink composition containing a
pigment, a polyfunctional polymerizable compound in which a content
ratio to a total polymerization component is 80% by mass or more
and a sensitizer in which a molecular weight is 1,000 or more onto
a recording substrate which is an aggregate of a nonabsorbable or a
low absorbable fiber material from an inkjet head under the
conditions in which an amount of ink droplets is from 25 pl to 200
pl and a distance between the recording substrate and the inkjet
head is from 5 mm to 20 mm, and a step of curing the image by
irradiating the formed image with an actinic ray under the
conditions in which an oxygen partial pressure is
1.5.times.10.sup.-2 MPa or less.
Inventors: |
MAKUTA; Toshiyuki;
(Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIFILM Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
FUJIFILM Corporation
Tokyo
JP
|
Family ID: |
50101774 |
Appl. No.: |
14/170300 |
Filed: |
January 31, 2014 |
Current U.S.
Class: |
347/47 ;
347/102 |
Current CPC
Class: |
D06P 5/30 20130101; B41M
7/0081 20130101; B41M 5/0064 20130101; B41J 11/002 20130101; B41M
5/0047 20130101; D06P 5/2005 20130101; D06P 1/44 20130101; B41J
3/407 20130101 |
Class at
Publication: |
347/47 ;
347/102 |
International
Class: |
B41J 11/00 20060101
B41J011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 19, 2013 |
JP |
2013-030385 |
Claims
1. An inkjet recording method comprising: an image forming step of
forming an image by imparting an actinic ray curable ink
composition containing a pigment, a polyfunctional polymerizable
compound in which a content ratio to a total polymerization
component is 80% by mass or more and a sensitizer in which a
molecular weight is 1,000 or more onto a recording substrate which
is an aggregate of a nonabsorbable or a low absorbable fiber
material from an inkjet head under the conditions in which an
amount of ink droplets is from 25 pl to 200 pl and a distance
between the recording substrate and the inkjet head is from 5 mm to
20 mm; and a curing step of curing the image by irradiating the
formed image with an actinic ray under the conditions in which an
oxygen partial pressure is 1.5.times.10.sup.-2 MPa or less.
2. The inkjet recording method according to claim 1, wherein in the
image forming step, the actinic ray curable ink composition is
imparted at a resolution from 50 dpi to 400 dpi.
3. The inkjet recording method according to claim 1, wherein in the
image forming step, the image is formed onto the recording
substrate which is transported at a transport speed of 50 m/min or
more.
4. The inkjet recording method according to claim 2, wherein in the
image forming step, the image is formed onto the recording
substrate which is transported at a transport speed of 50 m/min or
more.
5. The inkjet recording method according to claim 1, wherein the
fiber material is a polymer fiber.
6. The inkjet recording method according to claim 1, wherein the
polyfunctional polymerizable compound is a compound having at least
two or more radical polymerizable unsaturated double bonds.
7. The inkjet recording method according to claim 1, wherein the
amount of ink droplets of the actinic ray curable ink composition
is 75 pl or more.
8. The inkjet recording method according to claim 1, wherein the
resolution is from 50 dpi to 300 dpi.
9. The inkjet recording method according to claim 1, wherein the
image forming step includes a pre-curing step of pre-curing a first
actinic ray curable ink composition, after a first actinic ray
curable ink composition is imparted onto the recording substrate
and before a second actinic ray curable ink composition is imparted
by using the actinic ray curable ink composition of two or more
colors.
10. An inkjet recording device comprising: an inkjet head which
discharges an actinic ray curable ink composition containing a
pigment, a polyfunctional polymerizable compound in which a content
ratio to a total polymerization component is 80% by mass or more
and a sensitizer in which a molecular weight is 1,000 or more with
an amount of ink droplets from 25 pl to 200 pl; a transporting
means for transporting a recording substrate with a long shape
which is an aggregate of a nonabsorbable or a low absorbable fiber
material while a distance between the recording substrate and the
inkjet head is set to from 5 mm to 20 mm; and first irradiating
means for irradiating with respect to an image which is formed by
the actinic ray curable ink composition which is discharged from
the inkjet head with an actinic ray under the conditions in which
an oxygen partial pressure is 1.5.times.10.sup.-2 MPa or less.
11. The inkjet recording device according to claim 10, wherein the
inkjet head discharges the actinic ray curable ink composition with
the amount of ink droplets of 75 pl or more.
12. The inkjet recording device according to claim 10, wherein the
inkjet head has a plurality of nozzles which are arranged with the
nozzle density from 50 npi to 400 npi.
13. The inkjet recording device according to claim 10, wherein the
inkjet head has a plurality of nozzles which are arranged with the
nozzle density from 50 npi to 300 npi.
14. The inkjet recording device according to claim 10, comprising:
two or more inkjet heads; and second irradiating means for
pre-curing the actinic ray curable ink composition between the two
adjacent inkjet heads.
15. The inkjet recording device according to claim 10, wherein
first irradiating means includes inert gas supplying means for
supplying an inert gas and an irradiation chamber in which the
oxygen partial pressure is adjusted at 1.5.times.10.sup.-2 MPa or
less by the inert gas which is supplied from inert gas supplying
means and to which the recording substrate is transported.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an inkjet recording method
and an inkjet recording device.
[0003] 2. Description of the Related Art
[0004] Heretofore, in a case of printing onto a nonwoven fabric
used in a diaper (also including disposable pants), training pants,
an incontinence underwear for adult, or the like, a conventional
printing method such as flexography has been applied. In such a
conventional printing method, it is difficult to form an image well
on the nonwoven fabric since a plate directly comes into contact
with the nonwoven fabric. Therefore, after printing on a
polypropylene sheet in advance, placing a polypropylene sheet on
the nonwoven fabric was a general method.
[0005] However, in a case of producing a product by placing the
polypropylene sheet on the nonwoven fabric, this leads to a result
in which the breathability possessed by the nonwoven fabric becomes
impaired. Therefore, in a case where printing of an image having a
large area is performed, it was extremely difficult to ensure the
breathability.
[0006] As one of the methods to solve such a problem, it is
conceivable that an image is directly formed on the nonwoven fabric
by an inkjet method (for example, refer to JP4425914B and
JP2008-516807A). In the inkjet method, since an image is formed by
ink droplets (dot) which has been landed by spraying an ink, it is
possible to perform drawing without an inkjet head coming into
contact with the nonwoven fabric.
[0007] As an example of the ink which is used for the nonwoven
fabric, or the like, an aqueous ink has been proposed from the past
(for example, refer to JP2006-249203A and JP2011-513049A). The
aqueous ink has excellent safety for human bodies, compared with a
solvent based ink. Therefore, in respect of the safety, the aqueous
ink is suitable for an application of a diaper that may come into
contact with the skin, and the like.
[0008] On the other hand, a method of adding latex in ink is
considered as described in JP2011-513049A, from the viewpoint of
improvement of the adhesion of an image to the nonwoven fabric.
However, in a case where a step of printing onto the nonwoven
fabric is established to a manufacturing line, since an image
formation is required generally under 200 m/min to 500 m/min of
high-speed transport, from the viewpoint of achieving the high
productivity, it is difficult to maintain the high productivity by
using the aqueous ink. That is, in a case where the aqueous ink is
used, in order to fix an image on the nonwoven fabric, water has to
be dried, and thus a large-scale drying device is essential for
retaining the high productivity.
[0009] In addition, a technology in which an ultraviolet curable
ink is used for printing onto a cloth is disclosed (refer to
JP2012-158683A, JP2008-533217A and JP2003-508277A). The ultraviolet
curable ink can solve the problem of drying in the aqueous ink as
described above, that is, requiring a large drying device for
drying. In other words, since the ultraviolet curable ink is cured
at high-speed by an ultraviolet ray, it is possible to considerably
simplify a drying (curing) system.
SUMMARY OF THE INVENTION
[0010] However, the ultraviolet curable ink has a property in which
an uncured monomer easily remains in the ink when curing, and thus
there is a concern that it may not be safe for human bodies. In
addition, in the residual monomer in ink, there is a concern in
terms of the odor. Such the concerns are potentially more serious
in a case where an image is particularly formed on a sanitary
product such as a diaper which is worn by a baby.
[0011] In addition, in a case of using the nonwoven fabric as a
recoding medium, when the nonwoven fabric is transported at
high-speed, a travelling path of the nonwoven fabric tends to be
largely moved between the inkjet head and the nonwoven fabric, and
it is difficult to perform transporting at high-speed and to make
the travelling path of the nonwoven fabric stably show a certain
position. Therefore, when an image is formed, the nonwoven fabric
comes into contact with the inkjet head, and thus this may cause an
image to have trouble. On the other hand, if the interval between
the inkjet head and the nonwoven fabric is exceedingly separated,
the landing accuracy of ink droplets deteriorates as well as the
size of ink droplets has to be increased. Therefore, in the related
art, the relationship between enhancing the image formation
properties onto the nonwoven fabric and adding the high-speed
transport properties technically contrary to each other.
[0012] The present invention has been made in view of the above, an
object thereof is to provide an inkjet recording method in which an
image having favorable film strength, excellent rubfastness as well
as high safety and weak odor is formed and an inkjet recording
device.
[0013] In a case where an image is formed on a recording substrate
which is an aggregate of a fiber material such as the nonwoven
fabric, the findings described below were gained, and the present
invention has been achieved based on the findings. That is,
[0014] (1) the findings in which in a case of setting a nonwoven
fabric or the like which is an aggregate of a fiber material to a
recording substrate, since the travelling path of the recording
substrate is not stable, it is necessary to separate the recording
substrate and an inkjet head, in this case, in order to ensure an
image having a predetermined quality or more, ink droplets having
the predetermined size are required,
[0015] (2) the findings in which in an application in which a
nonwoven fabric or the like is used (for example, a sanitary
product such as a diaper), in order to ensure the safety when
coming into contact with human bodies (for example, the skin), a
polymerizable compound of bifunction or more is effective in terms
of reducing the elution as a residual monomer and the elution of a
residual alcohol component which is easily contaminated when a
monomer is used,
[0016] (3) the findings in which it is important to perform
irradiating with an actinic ray while suppressing the amount of
oxygen as much as possible in order to prevent even a trace of
elution of a residual monomer or the like,
[0017] (4) the findings in which changing a low molecular weight
sensitizer (example: thioxanthone based compound) which has been
widely used in the related art to the predetermined high molecular
compound is essential for enhancing the safety.
[0018] Specific means for solving the problem described above is
shown as follows.
[0019] <1> An inkjet recording method includes an image
forming step of forming an image by imparting an actinic ray
curable ink composition containing a pigment, a polyfunctional
polymerizable compound in which a content ratio to a total
polymerization component is 80% by mass or more and a sensitizer in
which a molecular weight is 1,000 or more onto a recording
substrate which is an aggregate of a nonabsorbable or a low
absorbable fiber material from an inkjet head under the conditions
in which an amount of ink droplets is from 25 pl to 200 pl and a
distance between the recording substrate and the inkjet head is
from 5 mm to 20 mm, and a curing step of curing the image by
irradiating the formed image with an actinic ray under the
conditions in which an oxygen partial pressure is
1.5.times.10.sup.-2 MPa or less.
[0020] <2> The inkjet recording method according to
<1>, in which in the image forming step, the actinic ray
curable ink composition is imparted at a resolution from 50 dpi
(dot per inch) to 400 dpi.
[0021] <3> The inkjet recording method according to <1>
or <2>, in which in the image forming step, the image is
formed onto the recording substrate which is transported at a
transport speed of 50 m/min or more.
[0022] <4> The inkjet recording method according to any one
of <1> to <3>, in which in the image forming step, the
image is formed by imparting all ink droplets which has to be
imparted in a direction which intersects a transport direction of
the recording substrate by discharging once.
[0023] <5> The inkjet recording method according to any one
of <1> to <4>, in which the fiber material is a polymer
fiber.
[0024] <6> The inkjet recording method according to any one
of <1> to <5>, in which the polyfunctional
polymerizable compound is a compound having at least two or more
radical polymerizable unsaturated double bonds.
[0025] <7> The inkjet recording method according to any one
of <1> to <6>, in which the actinic ray curable ink
composition further includes a photopolymerization initiator.
[0026] <8> The inkjet recording method according to any one
of <1> to <7>, in which the amount of ink droplets of
the actinic ray curable ink composition is 75 pl or more.
[0027] <9> The inkjet recording method according to any one
of <2> to <8>, in which the resolution is from 50 dpi
to 300 dpi.
[0028] <10> The inkjet recording method according to any one
of <2> to <9>, in which the resolution is from 50 dpi
to 200 dpi.
[0029] <11> The inkjet recording method according to any one
of <1> to <10>, in which the image forming step
includes a pre-curing step of pre-curing a first actinic ray
curable ink composition, after a first actinic ray curable ink
composition is imparted onto the recording substrate and before a
second actinic ray curable ink composition is imparted by using the
actinic ray curable ink composition of two or more colors.
[0030] <12> An inkjet recording device includes an inkjet
head which discharges an actinic ray curable ink composition
containing a pigment, a polyfunctional polymerizable compound in
which a content ratio to a total polymerization component is 80% by
mass or more and a sensitizer in which a molecular weight is 1,000
or more with an amount of ink droplets from 25 pl to 200 pl,
transporting means for transporting a recording substrate with a
long shape which is an aggregate of a nonabsorbable or a low
absorbable fiber material while a distance between the recording
substrate and the inkjet head is set to from 5 mm to 20 mm and
first irradiating means for irradiating with respect to an image
which is formed by the actinic ray curable ink composition which is
discharged from the inkjet head with an actinic ray under the
conditions in which an oxygen partial pressure is
1.5.times.10.sup.-2 MPa or less.
[0031] <13> The inkjet recording device according to
<12>, in which the inkjet head discharges the actinic ray
curable ink composition with the amount of ink droplets of 75 pl or
more.
[0032] <14> The inkjet recording device according to
<12> or <13>, in which the inkjet head has a plurality
of nozzles which are arranged with the nozzle density from 50 npi
to 400 npi.
[0033] <15> The inkjet recording device according to any one
of <12> or <14>, in which the inkjet head has a
plurality of nozzles which are arranged with the nozzle density
from 50 npi to 300 npi.
[0034] <16> The inkjet recording device according to any one
of <12> or <15>, in which the inkjet head has a
plurality of nozzles which are arranged with the nozzle density
from 50 npi to 200 npi.
[0035] <17> The inkjet recording device according to any one
of <12> or <16> includes two or more inkjet heads and
second irradiating means for pre-curing the actinic ray curable ink
composition between two adjoining inkjet heads between the two
adjacent inkjet heads.
[0036] <18> The inkjet recording device according to any one
of <12> or <17>, in which first irradiating means
includes inert gas supplying means for supplying an inert gas and
an irradiation chamber in which the oxygen partial pressure is
adjusted at 1.5.times.10.sup.-2 MPa or less by the inert gas which
is supplied from inert gas supplying means and to which the
recording substrate is transported.
[0037] According to the present invention, an inkjet recording
method in which an image having favorable film strength, excellent
rubfastness as well as high safety and weak odor is formed and an
inkjet recording device are provided.
BRIEF DESCRIPTION OF THE DRAWING
[0038] FIG. 1 is an entire configuration diagram schematically
illustrating an example of an inkjet recording device for carrying
out an inkjet recording method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Hereinafter, detailed description will be given of an inkjet
recording method and an inkjet recording device of the present
invention.
[0040] <Inkjet Recording Method>
[0041] The inkjet recording method of the present invention is
configured by providing with at least an image forming step of
forming an image by imparting an actinic ray curable ink
composition containing a pigment, a polyfunctional polymerizable
compound in which the content ratio to the total polymerization
component is 80% by mass or more and a sensitizer in which the
molecular weight is 1,000 or more onto the recording substrate
which is an aggregate of a nonabsorbable or a low absorbable fiber
material from the inkjet head under the conditions in which the
amount of ink droplets is from 25 pl to 200 pl and the distance
between the recording substrate and the inkjet head (hereinafter,
also referred to as the "slow distance") is from 5 mm to 20 mm, and
a curing step of curing the image by irradiating the formed image
with an actinic ray under the conditions in which the oxygen
partial pressure is 1.5.times.10.sup.-2 MPa or less.
[0042] In addition, the inkjet recording method of the present
invention may be configured by further providing with other steps
such as a pre-curing step of pre-curing the ink composition which
is imparted onto the recording substrate, a step of drying the
image or a step of heating and fixing the image, as necessary.
[0043] In the related art, as to an image formation technology
using the inkjet method, various kinds of examinations have been
conducted, however, in an application in which an aggregate of a
fiber material such as a nonwoven fabric is used as a recording
substrate (for example, a sanitary product such as a diaper), in
order to ensure the desired image formation properties and not to
impair the commercial value, compared with a general image
formation technology using plain paper, paper for exclusive use for
inkjet, or the like, more advanced conditions are required.
[0044] Specifically, in the aqueous ink which is generally used, in
order to fix the image on the nonwoven fabric, water has be dried,
furthermore, in order to realized high productivity, it is
necessary to prepare a large-scale drying device. In addition,
since the viscosity of the aqueous ink is generally low, the
aqueous ink easily becomes obstructive when transporting at
high-speed, moreover, in a case where the nonwoven fabric with a
long shape is transported at high-speed, it is difficult to
transport at a certain position, therefore, the travelling path is
dramatically changed. In order to avoid coming into contact with
the head, it is necessary to arrange the nonwoven fabric away from
the head, however, in order to ensure the landing position
accuracy, the size of ink droplets which are sprayed has to be
adjusted to a certain level or more. On the other hand, since it is
more difficult to discharge a large amount of ink droplets having
low viscosity than the inkjet head, the aqueous ink is unlikely to
form droplets in a large volume, and thus, it is disadvantageous to
adapt a system in which the gap between the head and the nonwoven
fabric has to be widened.
[0045] In consideration of this, in the present invention, by using
the polymerizable compound of bifunction or more as a curing
component configuring the actinic ray curable ink composition and
performing irradiation with rays for curing under a low oxygen
atmosphere, the residual monomer component and alcohol component
which easily remain in the image are reduced as well as by setting
the sensitizer for the cure acceleration to a predetermined high
molecular compound, the elution of the sensitize also is reduced.
In the present invention, since not only the unreacted
polymerizable compound is reduced by simply enhancing the curing
reactivity, but also the amount of the compound which remains in a
state which is easily eluted as an unreacted compound (the state in
which all of two or more polymerizable groups do not contribute to
the polymerization) is reduced by daringly selecting a
polyfunctional compound as a polymerizable compound, moreover, in a
case of using, for example, an ester based compound as a
polymerizable compound, the amount of alcohol component which does
not contribute to the reaction at all and remains among alcohols
which react with an acid when an ester is produced is also reduced,
the elution of the polymerizable compound and the alcohol component
itself which influences the safety is effectively reduced.
[0046] In addition, by setting the size of ink droplets to 25 pl or
more while retaining a predetermined interval between the recording
substrate and the inkjet head, a desired image is steadily formed
while avoiding the recording substrate coming into contact with the
head.
[0047] As stated above, an image having favorable film strength,
excellent rubfastness is obtained and the obtained image has
excellent safety and odor properties even in an embodiment of use
as coming into contact with humans (for example, the skin or the
like).
[0048] Hereinafter, detailed description will be given of each step
configuring the inkjet recording method of the present
invention.
[0049] --Image Forming Step--
[0050] In the image forming step in the present invention, the
image is formed by imparting the actinic ray curable ink
composition (hereinafter, simply referred to as an "ink
composition") onto the recording substrate which is an aggregate of
a nonabsorbable or a low absorbable fiber material from the inkjet
head under the following conditions of (1) and (2).
(1) Amount of ink droplets=25 pl to 200 pl (2) Distance of the
recording substrate and the inkjet head=5 mm to 20 mm
[0051] In the step, the actinic ray curable ink composition which
is discharged is configured by further using at least a pigment, a
polyfunctional polymerizable compound in which the content ratio to
the total polymerization component is 80% by mass or more and a
sensitizer in which the molecular weight is 1,000 or more and may
be configured by further using other components such as a resin
component, a organic solvent, other additive agents, as
necessary.
[0052] Imparting the ink composition onto the recording substrate
is performed by the inkjet method using the inkjet head. By using
the inkjet method, the ink is selectively imparted in the desired
area. The inkjet method is not particularly limited, and any
well-known method such as, for example, an electric charge control
method of discharging an ink by using electrostatic attraction, a
drop-on-demand method (pressure pulse method) of using vibration
pressure of piezo elements, a sound inkjet method of discharging an
ink by changing an electrical signal into a sound beam, irradiating
the ink and using radiation pressure, or a thermal inkjet (bubble
jet (registered product)) method of using the pressure that is
generated when the ink is heated and bubbles are formed may be
used.
[0053] In a case of imparting the ink onto the recording substrate,
as a method of imparting, a multi-pass or a one-pass (a
single-pass) may be used, however, a one-pass (a single-pass) or a
two-pass is preferable, from the viewpoint of high-speed recording.
Here, a one-pass means a recording method of recording by forming
all dots (ink droplets) which have to be formed in a scanning area
in the direction by discharging once in terms of the direction
which intersects the transport direction of the recording substrate
(the array direction of nozzles). In this case, a discharge head (a
line head in which the recording elements are arrayed) having the
length in accordance with the substrate width length is provided in
the substrate width direction which intersects the transport
direction of the recording substrate which is transported when
recording, and the ink is discharged in the nozzle array direction
from a plurality of discharge holes which are provided in the
discharge head at the same time. This is called a line method, and
it is possible to record the image on the entire surface of the
recording substrate by scanning the recording substrate in the
direction which intersects the array direction of the recording
elements. A transport system such as a carriage as a shuttle method
of recording while scanning a short length serial head in the width
direction (the main scanning direction) of the recording substrate
is not required. In addition, a two-pass means a method of
recording by forming dots which are formed in a scanning area by
discharging the ink twice.
[0054] .about.Amount of Ink Droplets.about.
[0055] In the image forming step in the present invention, the ink
composition is imparted onto the recording substrate with the
amount of ink droplets in a range from 25 pl to 200 pl. In a case
of increasing the slow distance in order to form the image on the
nonwoven fabric, when the size of droplets is less than 25 pl and
becomes too small, the discharge direction accuracy of the head
deteriorates as well as the landing position accuracy materially
deteriorates due to external factors such as wind. In a case of
forming the image on the nonwoven fabric, there are few cases
having the same landing position accuracy with commercial printing
or the like in which the image having high resolution is formed on
coated paper or the like is required, however, the amount of ink
droplets is set to 25 pl or more, from the viewpoint of ensuring
the image forming accuracy to the nonwoven fabric. In addition,
being 200 pl of the upper limit value of the amount of ink droplets
indicates the image density which is suitable for forming the image
having a certain level of resolution.
[0056] Among those, as the amount of ink droplets, from 75 pl to
200 pl is further preferable.
[0057] .about.Substrate/Distance Between Heads (Slow
Distance).about.
[0058] In a case of imparting the ink composition onto the
recording substrate, the distance between the recording substrate
and the inkjet head (the slow distance) is adjusted to a range from
5 mm to 20 mm.
[0059] In a case where, for example, the nonwoven fabric which is
an aggregate of the fiber material is molded in web-like and
transported at high-speed, it is difficult to transport while
maintaining the travelling path at a certain position, and a
phenomenon in which a track materially moves in between the
substrate/the head occurs. However, since this may cause the image
formation to have trouble when the head comes into contact with the
recording substrate, it is desired to expand the gap (the slow
distance) between the inkjet head and the surface of the nonwoven
fabric, from the viewpoint of avoiding the contact of the head.
When the slow distance is less than 5 mm, in a case of transporting
the web-like nonwoven fabric, or the like at high-speed, the
recording substrate comes into contact with the head. In addition,
when the slow distance exceeds 20 mm and becomes too big, it is
possible to avoid the concern of coming into contact with the head;
however, the landing position accuracy of ink droplets cannot be
ensured.
[0060] Among those, as the slow distance in a case of using an
aggregate of the fiber material such as the nonwoven fabric as the
recording substrate, a range from 10 mm to 20 mm is more
preferable.
[0061] It is difficult to increase the amount of ink droplets in
general due to limitations of the viscosity of the aqueous ink,
however, since it is easy to increase the viscosity in the actinic
ray curable ink composition in the present invention, ink droplets
in which the amount of ink droplets is relatively big are capable
of being discharged, and thus the adjustment of the slow distance
can be easily performed.
[0062] .about.Resolution.about.
[0063] In a case of forming the image with respect to an aggregate
of the fiber material such as the nonwoven fabric, since the image
quality having high-definition is not required so much,
furthermore, it is necessary to increase the amount of ink
droplets, as a resolution of the image (the image density), it is
preferable to set to a range from 50 dpi to 400 dpi. When the image
is formed at a resolution of 400 dpi or less, it is possible to
suppress to small the drying load without imparting the excess ink
on the nonwoven fabric, or the like, and thus it is possible to
obtain excellent curing properties. Therefore, the amount of the
unreacted residual monomer is suppressed to small and the odor
properties of the image become favorable. In addition, since the
solids are connected when the resolution is 50 dpi or more, the
occurrence of a void is prevented. In addition, the desired image
concentration is easily obtained.
[0064] Among those, for the same reasons described above, more
preferred resolution of the image is from 50 dpi to 300 dpi and
particularly preferred resolution of the image is from 50 dpi to
200 dpi.
[0065] .about.Pre-Curing Step.about.
[0066] In the image forming step, in a case of forming the image by
using the actinic ray curable ink composition of two or more
colors, after a first actinic ray curable ink composition is
imparted onto the recording substrate and before a second actinic
ray curable ink composition is imparted, a step of pre-curing by
irradiating the first actinic ray curable ink composition with
light (also referred to as a pinning exposure) is preferably
provided. The pinning exposure means an exposure method of
partially curing the ink composition which is imparted onto the
recording substrate with an amount of light that is insufficient to
complete curing.
[0067] In a case of forming the image having two or more colors,
since the viscosity of the ink on the substrate increases by
performing the pinning exposure for every single color, it is
possible to suppress the occurrence of the so-called color bleeding
between the colors.
[0068] The exposure amount of the pinning exposure for pre-curing
is preferably half or less and further preferably quarter or less,
with respect to the exposure amount for regular curing in a curing
step described later.
[0069] A light source which is used for pre-curing is not
particularly limited as long as the light source is one which emits
the wavelength light which promotes the polymerization-curing of
the ink composition, for example, the same light source as the
light source which can be used in the curing step described later
can be applied.
[0070] (Recording Substrate)
[0071] As the recording substrate in the present invention, an
aggregate of a nonabsorbable or a low absorbable fiber material is
used. The recording substrate indicates a material to be recorded
in which the image is recorded by the inkjet method.
[0072] Nonabsorbable or low absorbable indicates an absorption
degree of the aqueous ink of the recording substrate, however,
since the ink is aqueous, it is possible to evaluate as the
absorbability of water as describe below. In other words, in the
present invention, "nonabsorbable fibers" means fibers consisting
of compositions in which the coefficient of water absorption (% by
mass, 24 hours) is less than 0.2 by ASTM D570 in ASTM test method,
and "low absorbable fibers" means fibers consisting of compositions
in which the coefficient of water absorption (% by mass, 24 hours)
is 0.2 or more and less than 0.5 by ASTM D570 in ASTM test
method.
[0073] As the ink nonabsorbable or the low absorbable fiber
material, for example, synthetic fibers such as polyolefin fibers
(for example, fibers such as polypropylene, polyethylene),
polyester fibers (for example, fibers such as polyethylene
terephthalate, polyethylene naphthalate), aramid fibers, cellulose
fibers, nylon fibers, vinylon fibers, rayon fibers, metallic fibers
such as stainless, steel, iron, gold, silver, aluminum, glass
fibers (glass wool, or the like), and the like can be included.
[0074] As the aggregate of the ink nonabsorbable or the low
absorbable fiber material, for example, a nonwoven fabric, a
textile, a glass wool, and the like can be included.
[0075] The nonwoven fabric means a sheet-like nonwoven fabric which
entangles without weaving the fibers and includes a water stream
entanglement nonwoven fabric. The nonwoven fabric is a processing
sheet, a web or a butt of the fibers which are orientated in one
direction or randomly and adhered by friction, cohesiveness,
gluing, or the like. The nonwoven fabric dose not include a
nonwoven fabric which is weaved or knitted, a nonwoven fabric which
is tufted and is subjected to stitch bonding by incorporating the
bond of thread or filament, and a nonwoven fabric which is subject
to the felt process by a wet milling.
[0076] In the present invention, among those mentioned above, the
nonwoven fabric is preferable, and the nonwoven fabric of
polyolefin fibers is more preferable, from the viewpoint of low
cost and favorable workability.
[0077] In the recording substrate in the present invention, the
diameter (the fiber diameter) of a section perpendicular to the
fiber axial direction of the fibers which configure the recording
substrate is preferably 1 .mu.m to 200 .mu.m, more preferably 1
.mu.m to 100 .mu.m, and particularly preferably 5 .mu.m to 60
.mu.m. By the fiber diameter being 1 .mu.m or more, it is
advantageous, from the viewpoint of the image rub resistance and
the hardness of the recording substrate itself, and by being 200
.mu.m or less, it is advantageous, from the viewpoint of the image
bleeding or the texture of the recording substrate.
[0078] In addition, the thickness of the recording substrate is
preferably 1 .mu.m to 1,000 .mu.m, more preferably 1 .mu.m to 800
.mu.m, further preferably 5 .mu.m to 500 .mu.m, and particularly
preferably 5 .mu.m to 300 .mu.m. By the thickness being 1 .mu.m or
more, it is advantageous, from the viewpoint of the hardness of the
recording substrate itself, and by being 1,000 .mu.m or less, it is
advantageous, from the viewpoint of the texture of the recording
substrate.
[0079] The density of the recording substrate (the fiber surface
density) is preferably from 1 g/m.sup.2 to 300 g/m.sup.2, more
preferably from 1 g/m.sup.2 to 200 g/m.sup.2, and particularly
preferably from 5 g/m.sup.2 to 100 g/m.sup.2. By the fiber surface
density being 1 g/m.sup.2 or more, it is advantageous, from the
viewpoint of easily obtaining the image concentration, and by being
300 g/m.sup.2 or less, it is advantageous, from the viewpoint of
the rubfastness and the image bleeding.
[0080] Here, the fiber surface density indicates the ratio
[g/m.sup.2] of the amount of the fibers which exist on the surface,
to the area of the surface on which the fibers are
two-dimensionally distributed, and is the value which is determined
by cutting the recording substrate per unit area and measuring the
weight thereof.
[0081] The recording substrate (for example, the nonwoven fabric)
may be formed by any method such as melt blowing, span bonding,
solvent spinning, electro spinning, or carding.
[0082] The recording substrate in the present invention is
preferably subjected to a hydrophilic treatment. By being subjected
to the hydrophilic treatment, cissing of ink is prevented, and the
adhesion of the ink onto the fibers, specifically, the average
length of the ink which is adhered in the fiber axial direction can
be set to the predetermined range as described later.
[0083] At this time, the surface tension of the recording substrate
is preferably from 3.4.times.10.sup.-6 J to 4.5.times.10.sup.-6 J
(approximately 34 dyne/cm to 45 dyne/cm), and is more preferably
from 3.5.times.10.sup.-6 J to 4.0.times.10.sup.-6 J (approximately
35 dyne/cm to 40 dyne/cm). The surface tension of the substrate is
too small, there are some cases where the adhesion of the image
decreases and the surface tension of the substrate is too big,
there are some cases where the texture of the recording substrate
itself decreases.
[0084] Moreover, the surface tension of the recording substrate can
be measured the mixed liquid number in which the recording
substrate starts to be wet as the surface tension of the substrate
by using a mixed liquid for a wet tension test (manufactured by
Wako Pure Chemical Industries, Ltd.).
[0085] In this case, the surface tension of the ink is preferably
in a range from 20 mN/m to 40 mN/m, and in order to adjust the
average length of the ink which is adhered in the fiber axial
direction described later, it is possible to appropriately select
from the range described above. The surface tension of the ink is
measured by a Wilhelmy method using a static surface tension
measuring device (for example, TD3 manufactured by IKEDA SCIENTIFIC
CO., Ltd.).
[0086] The hydrophilic treatment includes a corona treatment, a
plasma treatment, a flame treatment, a heat treatment, an abrasion
treatment, a photo irradiation treatment (an UV treatment), or the
like, however, is not limited thereto.
[0087] In the present invention, for example, before the aqueous
ink is imparted and the image is recorded, the surface of the
recording substrate may be subjected to the corona treatment in
advance. The corona treatment can increase the surface energy of
the substrate and promote the wetness of the substrate surface and
the adhesiveness to the substrate. The corona treatment, for
example, can be conducted by using Corona master (manufactured by
Shinko Electric & Instrumentation Co., Ltd., PS-10S), or the
like. The conditions of the corona treatment have to be
appropriately selected in accordance with the situations such as
the type of the recording substrates or the ink compositions. For
example, the conditions may be set to the following treatment
conditions.
[0088] Treatment voltage: 10 kV to 15.6 kV
[0089] Treatment speed: 30 mm/s to 100 mm/s
[0090] As the hydrophilic treatment in the present invention, an
embodiment in which the corona treatment is conducted is
preferable, from the viewpoint of the cost and the workability.
[0091] (Actinic Ray Curable Ink Composition)
[0092] In the image forming step, the actinic ray curable ink
composition which is imparted on the recording substrate includes
at least a pigment, a polyfunctional polymerizable compound in
which the content ratio to the total polymerization component is
80% by mass or more and a sensitizer in which the molecular weight
is 1,000 or more and has the curing reactivity in which the
polymerization reaction is occurred by the curing component being
cured when irradiating with an actinic ray. By curing, the film
strength of the image which is formed on the recording substrate is
enhanced and the resistance (rubfastness) to rubbing from the
outside is improved.
[0093] [Pigment]
[0094] The actinic ray curable ink composition in the present
invention includes at least one kind of a pigment. By including the
pigment, it is possible to form the image having the desired
color.
[0095] As the pigment, there is no particularly limitation;
however, for example, the following organic pigments or inorganic
pigments described in the Color Index are included.
[0096] As a red or magenta pigment, Pigment Red 3, 5, 19, 22, 31,
38, 42, 43, 48:1, 48:2, 48:3, 48:4, 48:5, 49:1, 53:1, 57:1, 57:2,
58:4, 63:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 104, 108, 112, 122,
123, 144, 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185,
208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88,
Pigment Orange 13, 16, 20, 36, and the like are included.
[0097] As a blue or cyan pigment, Pigment Blue 1, 15, 15:1, 15:2,
15:3, 15:4, 15:6, 16, 17:1, 22, 27, 28, 29, 36, 60, and the like
are included.
[0098] As a green pigment, Pigment Green 7, 26, 36, 50, and the
like are included.
[0099] As a yellow pigment, Pigment Yellow 1, 3, 12, 13, 14, 17,
34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 120,
137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193,
and the like are included.
[0100] As a black pigment, Pigment Black 7, 28, 26, and the like
are included.
[0101] As a white pigment, Pigment White 6, 18, 21, and the like
are included.
[0102] It is preferable that the pigment be moderately dispersed in
the ink composition after being added to the ink composition. For
the dispersion of the pigment, for example, it is possible to use
various dispersion devices such as, for example, a ball mill, a
sand mill, an attritor, a roll mill, an agitator, a Henschel mixer,
a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet
mill, and a paint shaker.
[0103] The pigment may be added directly with each component during
preparation of the ink composition. In addition, in order to
improve the dispersibility, after adding to a solvent or a
dispersion medium such as the polymerizable compound in advance and
uniformly dispersing or dissolving, the pigment can be blended.
[0104] It is preferable to set dispersing agents, selection of the
dispersion medium, dispersion conditions, and filtration conditions
so that the average particle diameter of the pigment particles
which are included in the ink composition is preferably 0.005 .mu.m
to 0.5 .mu.m, more preferably 0.01 .mu.m to 0.45 .mu.m, further
preferably 0.015 .mu.m to 0.4 .mu.m. According to this particle
diameter management, clogging of the head nozzle is suppressed, and
it is possible to maintain storage stability, transparency and
curing sensitivity of the ink composition. According to this
particle diameter management, clogging of the head nozzle is
suppressed, and it is possible to maintain storage stability,
transparency and curing sensitivity of the ink composition.
[0105] One kind or two or more kinds of pigments can be
appropriately selected and used depending on the intended use of
the ink composition, or the like.
[0106] The content of the pigment in the ink composition is
appropriately selected according to the color and intended purpose;
however, is preferably from 0.01% by mass to 30% by mass, with
respect to the total ink composition.
[0107] The ink composition in the present invention preferably
contains a dispersing agent. In particular, in order to stably
disperse the pigment in the ink composition, it is preferable that
a dispersing agent be contained.
[0108] As the dispersing agent, a polymer dispersing agent is
preferable. Here, the term "polymer dispersing agent" in the
present invention means a dispersing agent in which the weight
average molecular weight is 1,000 or more.
[0109] As an example of the polymer dispersing agent,
DISPERBYK-101, DISPERBYK-102, DISPERBYK-103, DISPERBYK-106,
DISPERBYK-111, DISPERBYK-161, DISPERBYK-162, DISPERBYK-163,
DISPERBYK-164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-168,
DISPERBYK-170, DISPERBYK-171, DISPERBYK-174, DISPERBYK-182
(manufactured by BYK Japan Co., Ltd.); EFKA4010, EFKA4046,
EFKA4080, EFKA5010, EFKA5207, EFKA5244, EFKA6745, EFKA6750,
EFKA7414, EFKA745, EFKA7462, EFKA7500, EFKA7570, EFKA7575, EFKA7580
(manufactured by EFKA Additives); DISPERSE AID 6, DISPERSE AID 8,
DISPERSE AID 15, DISPERSE AID 9100 (manufactured by SAN NOPCO
LIMITED); various SOLSPERSE dispersing agents such as SOLSPERSE
3000, SOLSPERSE 5000, SOLSPERSE 9000, SOLSPERSE 12000, SOLSPERSE
13240, SOLSPERSE 13940, SOLSPERSE 17000, SOLSPERSE 22000, SOLSPERSE
24000, SOLSPERSE 26000, SOLSPERSE 28000, SOLSPERSE 32000, SOLSPERSE
36000, SOLSPERSE 39000, SOLSPERSE 41000 or SOLSPERSE 71000
(manufactured by Noveon); Adeka Pluronic L31, Adeka Pluronic F38,
Adeka Pluronic L42, Adeka Pluronic L44, Adeka Pluronic L61, Adeka
Pluronic L64, Adeka Pluronic F68, Adeka Pluronic L72, Adeka
Pluronic P95, Adeka Pluronic F77, Adeka Pluronic P84, Adeka
Pluronic F87, Adeka Pluronic P94, Adeka Pluronic L101, Adeka
Pluronic P103, Adeka Pluronic F108, Adeka Pluronic L121, Adeka
Pluronic P-123 (manufactured by ADEKA Corporation), Ionet S-20
(manufactured by Sanyo Chemical Industries Ltd.); Disparlon KS-860,
873SN, 874 (polymer dispersing agent), #2150 (aliphatic polyvalent
carboxylic acid), #7004 (polyether-ester type) (manufactured by
Kusumoto Chemicals, Ltd.), and the like are included.
[0110] The content of the dispersing agent in the ink composition
has to be appropriately selected according to intended purpose, or
the like; however, is preferably from 0.05% by mass to 15% by mass,
with respect to the total ink composition.
[0111] [Polyfunctional Polymerizable Compound]
[0112] The actinic ray curable ink composition in the present
invention includes at least one kind of a polyfunctional
polymerizable compound. By selecting a polymerizable compound of
bifunction or more as a polymerization component, since the amount
of the compound which remains in the state which is easily eluted
as an unreacted compound due to insufficient polymerization is
reduced, moreover, in a case of using, for example, an ester based
compound as a polymerizable compound, the amount of alcohol
component which does not contribute to the reaction at all and
remains out of alcohols which reacts with an acid when an ester is
produced is reduced, the elution of the polymerizable compound and
the alcohol component which remain in the image is reduced,
therefore the safety and the odor properties are dramatically
improved.
[0113] In the ink composition in the present invention, the content
ratio of the polyfunctional polymerizable compound is set to 80% by
mass or more, with respect to the total polymerization component.
That is to say, the content ratio of the monofunctional
polymerizable compound is less than 20% by mass, with respect to
the total polymerization component, furthermore, the content ratio
of the monofunctional polymerizable compound is preferably less
than 10% by mass, and a case where the monofunctional polymerizable
is not included is more preferable.
[0114] Here, the total polymerization component indicates all
compounds having a polymerizable group (for example, unsaturated
double bond) which contributes to the curing of the composition by
the polymerization reaction occurring by the light irradiation.
[0115] In a case where the polymerizable group remains as an
unreacted polymerizable group, since the unreacted compound remains
in the composition as it is, the monofunctional polymerizable
compound is not desired from the viewpoint of the safety and the
odor properties. In contrast, in a case of configuring by using the
polymerizable compound of bifunction or more, the probability in
which no polymerizable groups (example: acrylate group) which exist
in a molecule react is extremely low, and thus it is possible to
reduce the amount of the polymerizable compound which remains as a
monomer or the like in the composition. Furthermore, in a case of a
monofunctional monomer, for example, out of the polymerizable
compounds, in an ester monomer which is obtained by a monohydric
alcohol reacting with acrylic acid or methacrylic acid, there is a
case where an unreacted alcohol remains as impurities, and the
alcohol component is also one of the causes of the odor. In this
point, in a case of a monomer of bifunction or more, because of
being obtained by a dihydroxy alcohol or more reacting with acrylic
acid or methacrylic acid, the probability of no reaction with
acrylic acid or methacrylic acid is extremely low, and thus it is
possible to reduce the amount of alcohol which remains in the
composition, therefore it is effective to improve the odor
properties.
[0116] In the ink composition in the present invention, the content
ratio of the polyfunctional polymerizable compound is preferably
90% by mass or more, and a case of 100% by mass is more preferable,
with respect to the total polymerization component.
[0117] As the polyfunctional polymerizable compound, the
polyfunctional (meth)acrylate compound is suitably included. The
polyfunctional (meth)acrylate compound is a (meth)acrylate compound
of bifunction or more, and a (meth)acrylate monomer of bifunction
or more and a (meth)acrylate oligomer of bifunction or more are
included. Among the (meth)acrylate compound of bifunction or more,
a bifunctional acrylate compound is preferable, and diacrylate
monomer is particularly preferable.
[0118] In the present invention, the monomer is a compound in which
the molecular weight is less than 1,000 and the oligomer is
generally a polymer in which a finite number (generally 5 to 100)
of the monomers are bonded and a compound in which the weight
average molecular weight is 1,000 or more.
[0119] In addition, the (meth)acrylate monomer means a compound
which includes one or more (meth)acryloyloxy groups in a molecule
and in which the molecular weight is less than 1,000.
[0120] In the present invention, as the molecular weight of the
(meth)acrylate monomer, 700 or less is preferable, 500 or less is
more preferable, from 226 to 358 is further preferable, and from
242 to 300 is particularly preferable. When the molecular weight is
within the range described above, it is possible to achieve both of
the prevention of the elution from the image and the suppression of
the odor and the reactivity.
[0121] As the polyfunctional (meth)acrylate compound, a
di(meth)acrylate compound (di(meth)acrylate monomer) in which the
number of atoms of the main chain is 8 to 12 is suitably included
By including the di(meth)acrylate monomer, the image in which the
cross-linking properties are excellent, the elution of the film
component to the outside is suppressed, and the adhesion to the
substrate is excellent is easily obtained. In addition, the
di(meth)acrylate monomer gives moderate flexibility to the cured
film, and the viscosity thereof is low as a monomer, therefore it
is suitable to give the ink composition having excellent discharge
properties.
[0122] Among the di(meth)acrylate monomers described above, a
compound represented by the following general formula (a-1-1) is
preferable.
##STR00001##
[0123] In the general formula (a-1-1), R.sup.A1 represents a
divalent linking group in which the number of atoms of the main
chain is 8 to 12 and two R.sup.A2s each independently represent a
hydrogen atom and a methyl group.
[0124] "The number of atoms of the main chain" in "a divalent
linking group in which the number of atoms of the main chain is 8
to 12" represented by R.sup.A1 means that the shortest number of
atoms which configures the main chain connected with the linking
part with two sites of acrylate groups of R.sup.A1 is 8 to 12. In a
case where the main chain has an ether bond (--O--), an oxygen atom
which configures an ether bond is also included. The atom of the
main chain is preferably a carbon atom or an oxygen atom.
[0125] More specifically, in a case where the compound represented
by the general formula (a-1-1) is diethylene glycol diacrylate, the
number of atoms of the main chain is 5, and in a case of ethylene
oxide modified neopentyl glycol diacrylate (both ends ethylene
oxide 1 mol modified neopentyl glycol diacrylate), the number of
atoms of the main chain is 9.
[0126] As R.sup.A2, a hydrogen atom is preferable. In addition, two
R.sup.A2s may be composed of the same or different groups, however,
they are preferably the same, from the viewpoint of synthesis.
[0127] As examples of the compound represented by the general
formula (a-1-1), ethylene oxide (EO) modified neopentyl glycol
di(meth)acrylate (the number of atoms of the main chain=9),
propylene oxide (PO) modified neopentyl glycol di(meth)acrylate
(the number of atoms of the main chain=9), EO modified hexanediol
di(meth)acrylate (the number of atoms of the main chain=9), PO
modified hexanediol di(meth)acrylate (the number of atoms of the
main chain=9), octane diol di(meth)acrylate, nonanediol
di(meth)acrylate (the number of atoms of the main chain=9), decane
diol di(meth)acrylate (the number of atoms of the main chain=10),
dodecane diol di(meth)acrylate (the number of atoms of the main
chain=12), tripropylene glycol di(meth)acrylate (the number of
atoms of the main chain=8), triethylene glycol di(meth)acrylate
(the number of atoms of the main chain=8), and the like are
included. Among those, triethylene glycol diacrylate and PO
modified neopentyl glycol diacrylate are preferable, from the
viewpoint of the suppression of the elution from the image and the
odor and the viewpoint of the flexibility of the cured film.
[0128] The compound represented by the general formula (a-1-1) may
be used either alone or as a combination of two or more.
[0129] The content of the compound represented by the general
formula (a-1-1) is preferably from 10% by mass to 80% by mass, more
preferably from 15% by mass to 75% by mass, and particularly
preferably from 20% by mass to 45% by mass, with respect to the
total ink composition.
[0130] In addition, as the polyfunctional (meth)acrylate compound,
apart from the above, for example, a bifunctional (meth)acrylate
monomer such as dipropylene glycol di(meth)acrylate, tetraethylene
glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate,
3-methylpentanediol di(meth)acrylate, hexanediol di(meth)acrylate,
heptanediol di(meth)acrylate; and a (meth)acrylate compound of
trifunction or more such as pentaerythritol tri(meth)acrylate,
pentaerythritol tetra(meth)acrylate, dipentaerythritol
tetra(meth)acrylate, trimethylolethane tri(meth)acrylate,
trimethylol propane tri(meth)acrylate, tetramethylol methane
tetra(meth)acrylate, oligoester (meth)acrylate are suitably
included.
[0131] SR341, SR350, and the like manufactured by Sartomer Co. Inc.
are included as an example of the commercial product of a
commercially available polyfunctional (meth)acrylate compound.
[0132] In the polyfunctional (meth)acrylate monomer, the viscosity
as a monomer unit is preferably from 3 mPas to 20 mPas, and more
preferably from 6 mPas to 15 mPas at 25.degree. C.
[0133] As the polyfunctional (meth)acrylate monomer, a bifunctional
acrylate monomer is preferable, from the viewpoint of forming a
cross-linked structure on the cured film and suppressing the
elution from the image and the odor. In a case of including the
bifunctional acrylate monomer as the polyfunctional polymerizable
compound, the content of the bifunctional acrylate monomer is
preferably from 10% by mass to 80% by mass, more preferably from
15% by mass to 75% by mass, and further preferably from 20% by mass
to 45% by mass, with respect to the total mass of ink
composition.
[0134] In addition, in a case of including the (meth)acrylate
monomer of trifunction or more as the polyfunctional polymerizable
compound, the content of the (meth)acrylate monomer of trifunction
or more is preferably 30% by mass or less, more preferably 20% by
mass or less, and further preferably 15% by mass or less, with
respect to the total ink composition.
[0135] In addition, the ink composition may include a
monofunctional polymerizable compound (example: (meth)acrylate
monomer) described later, and in this case, as the content of the
monofunctional polymerizable compound, 60% by mass or less is
preferable, and 50% by mass or less is more preferable, with
respect to the total ink composition, from the viewpoint of
suppressing the elution from the image, the odor and the
blocking.
[0136] The ink composition in the present invention may include the
polyfunctional (meth)acrylate oligomer as a polyfunctional
polymerizable compound. The oligomer is a polymer in which a finite
number (generally 5 to 100) of the monomers are generally bonded
and it is possible to arbitrarily select well-known oligomers
having two or more (meth)acryloyloxy groups.
[0137] The polyfunctional (meth)acrylate oligomer is a compound
which includes at least two (meth)acryloyloxy groups, and among
those, the bi- to hexafunctional compound is preferable, the bi- to
tetrafunctional compound is more preferable, the bifunctional or
trifunctional compound is further preferable, and the bifunctional
compound is particularly preferable.
[0138] Among the polyfunctional (meth)acrylate oligomers, the
polyfunctional acrylate oligomer is preferable.
[0139] The weight average molecular weight of the polyfunctional
(meth)acrylate oligomer is preferably 1,000 or more, more
preferably from 1,000 to 5,000, further preferably from 1,500
4,500, and particularly preferably from 2,000 to 4,000. When the
weight average molecular weight is within the range described
above, the elution from the cured film (the image) and the odor are
effectively prevented.
[0140] In addition, in a case where the oligomer has the molecular
weight distribution, the component in which the molecular weight is
1,000 or less is preferably 5% by mass or less, with respect to the
total polyfunctional (meth)acrylate oligomer, from the viewpoint of
preventing the elution from the cured film (image).
[0141] As the polyfunctional (meth)acrylate oligomer, oligoester
(meth)acrylate is preferable, and among those, urethane
(meth)acrylate, polyester (meth)acrylate and epoxy (meth)acrylate
are more preferable, and urethane (meth)acrylate is further
preferable.
[0142] As urethane (meth)acrylate, aliphatic urethane
(meth)acrylate and aromatic urethane (meth)acrylate are preferably
included, however, aliphatic urethane (meth)acrylate is more
preferably included. In addition, urethane (meth)acrylate is
preferably urethane (meth)acrylate of tetrafunction or less, and
bifunctional urethane (meth)acrylate is more preferable.
[0143] By including urethane (meth)acrylate, the ink composition
having excellent adhesion of the substrate and excellent curing
properties is obtained.
[0144] As to the polyfunctional (meth)acrylate oligomer, Oligomer
Handbook (Junji FURUKAWA supervision, The Chemical Daily Co., Ltd.)
can be also referred.
[0145] As the polyfunctional (meth)acrylate oligomer, the
commercial products may be used. As an example of the commercial
product, the products described below are included.
[0146] As urethane (meth)acrylate, for example, R1204, R1211,
R1213, R1217, R1218, R1301, R1302, R1303, R1304, R1306, R1308,
R1901, R1150, and the like manufactured by DAI-ICHI KOGYO SEIYAKU
CO., LTD., EBECRYL series (for example, EBECRYL 230, 270, 4858,
8402, 8804, 8807, 8803, 9260, 1290, 1290K, 5129, 4842, 8210, 210,
4827, 6700, 4450, 220) manufactured by Daicel-Cytec Co., Ltd., NK
OLIGO U-4HA, U-6HA, U-15HA, U-108A, U200AX, and the like
manufactured by SHIN-NAKAMURA CHEMICAL CO., LTD., and ARONIX
M-1100, M-1200, M-1210, M-1310, M-1600, M-1960, and the like
manufactured by TOAGOSEI CO., LTD. are included.
[0147] As polyester (meth)acrylate, for example, EBECRYL series
(for example, EBECRYL770, IRR467, 81, 84, 83, 80, 675, 800, 810,
812, 1657, 1810, IRR302, 450, 670, 830, 870, 1830, 1870, 2870,
IRR267, 813, IRR483, 811, and the like) manufactured by
Daicel-Cytec Co., Ltd., and ARONIX M-6100, M-6200, M-6250, M-6500,
M-7100, M-8030, M-8060, M-8100, M-8530, M-8560, M-9050, and the
like manufactured by TOAGOSEI CO., LTD. are included.
[0148] In addition, as epoxy (meth)acrylate, for example, EBECRYL
series (for example, EBECRYL600, 860, 2958, 3411, 3600, 3605, 3700,
3701, 3703, 3702, 3708, RDX63182, 6040, and the like) manufactured
by Daicel-Cytec Co., Ltd., and the like are included.
[0149] The polyfunctional (meth)acrylate oligomer may be used
either alone or as a combination of two or more.
[0150] The content of the polyfunctional (meth)acrylate oligomer is
preferably 15% by mass or less and more preferably 10% by mass or
less, with respect to the total ink composition.
[0151] [Monofunctional Polymerizable Compound]
[0152] The actinic ray curable ink composition in the present
invention can be configured by using the polyfunctional
polymerizable compound described above and the monofunctional
polymerizable compound together.
[0153] As an example of the monofunctional polymerizable compound,
a monofunctional (meth)acrylate compound is suitably included. As
the monofunctional (meth)acrylate compound, a compound selected
from a group consisting of a monofunctional (meth)acrylate compound
having a hydrocarbon group having 9 or 10 carbon atoms in a
molecule and a monofunctional (meth)acrylate compound having a
aromatic group is preferable.
[0154] The monofunctional (meth)acrylate compound having a
hydrocarbon group having 9 or 10 carbon atoms in a molecule is more
preferably a monofunctional acrylate compound having a hydrocarbon
group having 9 or 10 carbon atoms in a molecule. If the compound is
used together, since the film strength is enhanced and the
migration of a low molecular weight component in the cured film
(the image) is suppressed, it is possible to obtain the image
having excellent suppression of the elution from the image and the
odor.
[0155] Generally, the monofunctional (meth)acrylate compound having
a hydrocarbon group having 9 or 10 carbon atoms is easily subjected
to the polymerization inhibition by oxygen and there are some cases
where a problem occurs in terms of the curing properties in the
atmosphere. In the present invention, since an actinic ray is
irradiated under the low oxygen partial pressure, the degree of the
polymerization inhibition by oxygen is low, and thus it is possible
to obtain excellent cured characteristics.
[0156] Moreover, for example, a dicyclopentenyl group described
later has an unsaturated bond in an aliphatic ring, however, due to
the extremely low polymerizability, such an unsaturated bond does
not apply to a polymerizable group mentioned in the present
invention.
[0157] Among the monofunctional polymerizable compounds, a compound
represented by the following general formula (a-2-1) is
preferable.
##STR00002##
[0158] In the general formula (a-2-1), R.sup.A10 represents a
hydrogen atom or a methyl group, R.sup.A11 resents a single bond or
a (poly)alkyleneoxy group, and R.sup.A12 represents a hydrocarbon
group having 9 or 10 carbon atoms.
[0159] As R.sup.A10, a hydrogen atom is preferable.
[0160] A "(poly)alkyleneoxy group" represented by R.sup.A11
represents an alkyleneoxy group or a polyalkyleneoxy group which
two or more alkyleneoxy groups are bonded. As an alkyleneoxy group,
an ethyleneoxy group or a propyleneoxy group is preferable, and an
ethyleneoxy group is more preferable. R.sup.A11 is particularly
preferably a single bond or an ethyleneoxy group.
[0161] The hydrocarbon group having 9 or 10 carbon atoms
represented by R.sup.A12 is preferably a cyclic hydrocarbon group.
The cyclic hydrocarbon group may be monocycle or polycycle,
however, preferably has a polycyclic structure. In addition, the
cyclic hydrocarbon group may be a saturated hydrocarbon ring or an
unsaturated hydrocarbon ring having an unsaturated bond, and is not
particularly limited. Here, the hydrocarbon group having 9 or 10
carbon atoms means not only carbons which forms a ring but also the
number of all carbons in R.sup.A12.
[0162] As the compound represented by the general formula (a-2-1),
isobornyl (meth)acrylate, 3,3,5-trimethyl cyclohexyl acrylate,
4-t-butyl cyclohexyl (meth)acrylate, dicyclopentanyl
oxyethyl(meth)acrylate, dicyclopentanyl (meth)ethyl acrylate,
dicyclopentenyloxyethyl (meth)acrylate, dicyclopentenyl
(meth)acrylate, and the like are exemplified, and 4-t-butyl
cyclohexyl acrylate and dicyclopentenyloxyethyl acrylate are more
preferable, from the viewpoint of the odor and the low
volatility.
[0163] The content of the compound represented by the general
formula (a-2-1) is preferably 5% by mass to 50% by mass, more
preferably 10% by mass to 45% by mass, and further preferably 15%
by mass to 35% by mass, with respect to the total ink composition.
If the content of the compound is within the range described above,
the image in which the elution amount of the polymerizable compound
and the occurrence of the odor are suppressed is obtained.
[0164] As the monofunctional (meth)acrylate compound, the
monofunctional (meth)acrylate compound having an aromatic group is
suitably included. The cyclic structure of an aromatic group of the
monofunctional (meth)acrylate compound having an aromatic group may
include a heteroatom such as O, N, or S. As the monofunctional
(meth)acrylate compound having an aromatic group, a compound
represented by the following general formula (a-2-2) is
preferable.
##STR00003##
[0165] In the compound represented by the general formula (a-2-2),
R.sup.A20 represents a hydrogen atom or a methyl group. R.sup.A21
represents a single bond, an ether bond (--O--), an ester bond
(--C(O)O-- or --OC(O)--), an amide bond (--C(O)NH-- or --NHC(O)--),
a carbonyl bond (--C(O)--), an alkylene group having 20 or less
carbon atoms which may have a branch, or a linking group formed by
a combination thereof, and is preferably a single bond, or one
having a group or a bond selected from a group consisting of an
ether group, an ester group and an alkylene group having 20 or less
carbon atoms R.sup.A22 represents an aromatic group containing a
monocyclic aromatic group or a polycyclic aromatic group. The
cyclic structure of an aromatic group may include a heteroatom such
as O, N, or S.
[0166] The aromatic group represented by R.sup.A22 is not
particularly limited, however, is preferably a polycyclic aromatic
group having 2 to 4 rings in addition to a phenyl group which is a
monocyclic aromatic.
[0167] As an example of the aromatic group, a naphthyl group, a
naphthydiyl group, a naphthytriyl group, an anthryl group, an
anthrydiyl group, an anthrytriyl group, a 1H-indenyl group, a
1H-indendiyl group, a 1H-indentriyl group, a 9H-fluorenyl group, a
9H-fluorendiyl group, a 9H-fluorentriyl group, a 1H-phenalenyl
group, a 1H-phenalendiyl group, a 1H-phenalentriyl group, a
phenanthrenyl group, a phenanthrendiyl group, a phenanthrentriyl
group, a triphenylenyl group, a triphenylendiyl group, a
triphenylentriyl group, a pyrenyl group, a pyrendiyl group, a
pyrentriyl group, a naphthacenyl group, a naphthacendiyl group, a
naphthacentriyl group, a tetraphenyl group, a tetraphendiyl group,
a tetraphentriyl group, a biphenylenyl group, a biphenylendiyl
group, a biphenylentriyl group, an a s-indacenyl group, an a
s-indacendiyl group, an a s-indacentriyl group, a s-indacenyl
group, a s-indacendiyl group, a s-indacentriyl group, an
acenaphthylenyl group, an acenaphthylendiyl group, an
acenaphthylentriyl group, a fluoranthenyl group, a fluoranthendiyl
group, a fluoranthentriyl group, an acephenantolylenyl group, an
acephenantolylendiyl group, an acephenantolylentriyl group, an
aceanthrylenyl group, an aceanthrylendiyl group, an
aceanthrylentriyl group, a chrysenyl group, a chrysendiyl group, a
chrysentriyl group, a pleiadenyl group, a pleiadendiyl group, a
pleiadendiyl group, and the like are included.
[0168] These aromatic groups may be an aromatic heterocyclic group
containing a heteroatom such as O, N, or S. Specifically, the
monocyclic aromatic heterocyclic groups such as a fluyl group, a
furandiyl group, a furantriyl group, a thiophenyl group, a
thiophendiyl group, a thiophentriyl group, a 1H-pyrrolyl group, a
1H-pyrroldiyl group, a 1H-pyrroltriyl group, a 2H-pyrrolyl group, a
2H-pyrroldiyl group, a 2H-pyrroltriyl group, a 1H-pyrazolyl group,
a 1H-pyrazoldiyl group, a 1H-pyrazoltriyl group, a 1H-imidazolyl
group, a 1H-imidazoldiyl group, a 1H-imidazoltriyl group, an
isoxazolyl group, an isoxazoldiyl group, an isoxazoltriyl group, an
isothiazolyl group, an isothiazoldiyl group, an isothiazoltriyl
group, a 2H-pyranyl group, a 2H-pyrandiyl group, a 2H-pyrantriyl
group, a 2H-thiopyranyl group, a 2H-thiopyrandiyl group, a
2H-thiopyrantriyl group, a pyridiyl group, a pyridindiyl group, a
pyridintriyl group, a pyridazinyl group, a pyridazindiyl group, a
pyridazintriyl group, a pyrimidinyl group, a pyrimidindiyl group, a
pyrimidintriyl group, a pyrazinyl group, a pyrazindiyl group, a
pyrazintriyl group, a 1,2,3-triazolyl group, a 1,2,3-triazoldiyl
group, a 1,2,3-triazoltriyl group, a 1,2,4-triazolyl group, a
1,2,4-triazoldiyl group, or a 1,2,4-triazoltriyl group are
included.
[0169] In addition, the polycyclic aromatic heterocyclic groups
such as a thianthrenyl group, a thianthrendiyl group, a
thianthrentriyl group, an isobenzofuranyl group, an
isobenzofurandiyl group, an isobenzofurantriyl group, an
isochromenyl group, an isochromendiyl group, an isochromentriyl
group, a 4H-chromenyl group, a 4H-chromendiyl group, a
4H-chromentriyl group, a xanthenyl group, a xanthendiyl group, a
xanthentriyl group, a phenoxathiinyl group, a phenoxathiindiyl
group, a phenoxathiintriyl group, an indoliznyl group, an
indolizindiyl group, an indolizintriyl group, an isoindolyl group,
an isoindoldiyl group, an isoindoltriyl group, an indolyl group, an
indoldiyl group, an indoltriyl group, an indazolyl group, an
indazoldiyl group, an indazoltriyl group, a purinyl group, a
purindiyl group, a purintriyl group, a 4H-quinolizinyl group, a
4H-quinolizindiyl group, a 4H-quinolizintriyl group, an isoquinolyl
group, an isoquinolidiyl group, an isoquinolitriyl group, a
quinolyl group, a quinolidiyl group, a quinolitriyl group, a
phthalazinyl group, a phthalazindiyl group, a phthalazintriyl
group, a naphthyridinyl group, a naphthyridindiyl group, a
naphthyridintriyl group, a quinoxalinyl group, a quinoxalindiyl
group, a quinoxalintriyl group, a quinazolinyl group, a
quinazolindiyl group, a quinazolintriyl group, a cinnolinyl group,
a cinnolindiyl group, a cinnolintriyl group, a pteridinyl group, a
pteridindiyl group, a pteridintriyl group, a carbazolyl group, a
carbazoldiyl group, a carbazoltriyl group, a .beta.-carbolinyl
group, a .beta.-carbolinediyl group, a .beta.-carbolinetriyl group,
a phenanthridinyl group, a phenanthridindiyl group, a
phenanthridintriyl group, an acridinyl group, an acridindiyl group,
an acridintriyl group, a perimidinyl group, a perimidindiyl group,
a perimidintriyl group, a phenanthrolinyl group, a
phenanthrolindiyl group, a phenanthrolintriyl group, a phenazinyl
group, a phenazindiyl group, a phenazintriyl group, a
phenothiazinyl group, a phenothiazindiyl group, a phenothiazintriyl
group, a phenoxazinyl group, a phenoxazindiyl group, a
phenoxazintriyl group, a pyrrolizinyl group, a pyrrolizindiyl
group, or a pyrrolizintriyl group are included.
[0170] The aromatic group described above may have one or two or
more halogen atoms, hydroxyl groups, amino groups, thiol groups,
siloxane groups or substituents having 30 or less carbon atoms. For
example, such as phthalic anhydride or a phthalimide anhydride, the
cyclic structure including a heteroatom such as O, N, or S may be
formed by two or more substituents in which aromatic groups
have.
[0171] Among those, as the monofunctional (meth)acrylate monomer
having an aromatic group, phenoxyethyl (meth)acrylate is
particularly preferable and phenoxyethyl acrylate is most
preferable.
[0172] In addition, as the monofunctional (meth)acrylate compound,
a monofunctional (meth)acrylate compound having a long chain alkyl
group which has 12 to 18 carbon atoms in a molecule is suitably
included. By having a long chain alkyl group which has 12 or more
carbon atoms in a molecule, the elution amount is reduced and the
odor is suppressed.
[0173] As the monofunctional (meth)acrylate compound having a long
chain alkyl group which has 12 to 18 carbon atoms in a molecule, a
compound represented by the following general formula (a-2-3) is
preferable.
##STR00004##
[0174] In the general formula (a-2-3), R.sup.A30 represents a
hydrogen atom or a methyl group and R.sup.A31 represents an alkyl
group having 12 to 18 carbon atoms.
[0175] As R.sup.A30, a hydrogen atom is preferable. In addition, an
alkyl group having 12 to 18 carbon atoms represented by R.sup.A31
may be either linear or branched, however, linear is
preferable.
[0176] As an example of the compound represented by the general
formula (a-2-3), lauryl (meth)acrylate, tridecyl (meth)acrylate,
and stearyl (meth)acrylate are included.
[0177] The compound represented by the general formula (a-2-3) may
be used either alone or as a combination of two or more. As the
content of the compound represented by the general formula (a-2-3),
from 2% by mass to 20% by mass is preferable, and from 3% by mass
to 15% by mass is more preferable, with respect to the total ink
composition.
[0178] Furthermore, as the monofunctional (meth)acrylate compound,
other monofunctional (meth)acrylate compounds may be included other
than the above.
[0179] As other monofunctional (meth)acrylate compound other than
the above, an N-vinyl lactam based compound may be included. As the
N-vinyl lactam based compound, a compound represented by the
following general formula (A) is preferable.
##STR00005##
[0180] In the general formula (A), n represents an integer of 2 to
6, n is preferably an integer of 3 to 6, n is more preferably 3 or
5, and 5 (that is, N-vinyl caprolactam) is particularly preferable,
from the viewpoint of the flexibility after the ink composition is
cured, the adhesion with the recording substrate, and the
availability of a raw material. N-vinyl caprolactam has excellent
safety, is widely used, can be obtained at a relatively low price,
and in particular, the favorable curing properties and adhesion to
the medium to be recorded of the cured film are obtained, which is
therefore preferable.
[0181] In addition, the N-vinyl lactam based compound may have a
substituent such as an alkyl group or an aryl group on a lactam
ring, and may be linked to a saturated or unsaturated ring
structure.
[0182] The N-vinyl lactam based compound may be used either alone
or as a combination of two or more.
[0183] The content of the N-vinyl lactam based compound is
preferably from 5% by mass to 40% by mass, more preferably from 10%
by mass to 35% by mass, and further preferably from 15% by mass to
30% by mass, with respect to the total mass of the ink composition.
When the content of the N-vinyl lactam based compound is in the
range described above, the image having excellent flexibility is
easily obtained.
[0184] The ink composition in the present invention may be used
other polymerizable compounds other than the above.
[0185] As an example of other polymerizable compounds, an
unsaturated carboxylic acid such as itaconic acid, crotonic acid,
isocrotonic acid or maleic acid, and a salt thereof, an anhydride
having an ethylenic unsaturated group, acrylonitrile, and styrene,
furthermore, various unsaturated polyesters, unsaturated
polyethers, unsaturated polyamides and unsaturated urethane, a
(meth)acrylamide compound, and a radical polymerizable compound
such as a vinyl ether compound are included.
[0186] Furthermore, as other polymerizable compounds, the
commercial products or the well-known radical polymerizable or
linkable monomers, oligomers and polymers in the industry which are
described in "Crosslinking Agent Handbook" edited by shinzo
YAMASHITA (1981, TAISEISHA LTD.); "UV.cndot.EB Curing Handbook (raw
material edition)" edited by kiyomi KATO (1985, the publishing
association of polymer); "Application and Market of UV.cndot.EB
Curing Technology" edited by RadTech Japan, page 79 (1989, CMC
Publishing CO., LTD.); "Polyester Resin Handbook" written by
eiichiro TAKIYAMA (1988, NIKKAN KOGYO SHIMBUN LTD.), or the like
can be used.
[0187] The molecular weight of other polymerizable compound is
preferably from 80 to 2,000, more preferably from 80 to 1,000, and
further preferably from 80 to 800.
[0188] In addition, in a case of including other polymerizable
compound, the content of other polymerizable compound in the ink
composition is preferably from 1% by mass to 40% by mass, more
preferably from 3% by mass to 30% by mass, particularly preferably
from 5% by mass to 25% by mass, with respect to the total mass of
the ink composition.
[0189] [Sensitizer]
[0190] The actinic ray curable ink composition in the present
invention includes at least one kind of a sensitizer in which the
molecular weight is 1,000 or more. A low molecular weight compound
which is generally used as a sensitizer (for example, a
thioxanthone compound such as ITX (isoproropyl thioxanthone)) tends
to elute from a printed matter into food goods and to be easily
contaminated, therefore, a case of applying to a sanitary product
such as a diaper in which there is a possibility to come into
contact with the skin is also concerned. In a case of using the
sensitizer together, by selecting the sensitizer having the large
molecular weight, the elution of the sensitizer is suppressed, from
the viewpoint of improving the reactivity of the polymerizable
compound. In this manner, the image having favorable film strength
is realized, as well as the safety and the odor properties of the
image are dramatically improved.
[0191] As the sensitizer in which the molecular weight is 1,000 or
more, a compound represented by the following general formula (1)
is preferable.
##STR00006##
[0192] In the general formula (1), R.sup.1 and R.sup.2 each
independently represent an alkyl group having 1 to 5 carbon atoms
or a halogen atom, j represents an integer of 0 to 4, k represents
an integer of 0 to 3, x represents an integer of 2 to 4, and when j
and k are an integer of 2 or more, R.sup.1s and R.sup.2s which
plurally exist may be respectively the same as or different from
each other, and X.sup.1 represents a x valent hydrocarbon chain
having 2 to 300 carbon atoms which may include an ether bond and/or
an ester bond.
[0193] In the general formula (1), le and R.sup.2 each
independently represent an alkyl group having 1 to 5 carbon atoms
or a halogen atom.
[0194] The alkyl group having 1 to 5 carbon atoms may be any of
linear, branched or cyclic, however, linear or branched is
preferable, an alkyl group having 1 to 4 carbon atoms is
preferable, an alkyl group having 2 or 3 carbon atoms is more
preferable, and an ethyl group or a isopropyl group is further
preferable.
[0195] As the halogen atom, a fluorine atom, a chlorine atom, a
bromine atom and an iodine atom are exemplified and a chlorine atom
is preferable.
[0196] Among those mentioned above, R.sup.1 and R.sup.2
particularly preferably an ethyl group, an isopropyl group or a
chlorine atom.
[0197] In the general formula (1), j represents an integer of 0 to
4, is preferably 0 to 2, and is more preferably 0 or 1. In a case
where j is in integer of 2 or more, R's which is in multiple
numbers may be composed of the same or different groups.
[0198] In the general formula (1), k represents an integer of 0 to
3, is preferably 0 to 2, is more preferably 0 or 1, and is further
preferably 0 In a case where k is in integer of 2 or more, R.sup.2s
which is in multiple numbers may be composed of the same or
different groups.
[0199] In the general formula (1), x represents an integer of 2 to
4, is more preferably 3 or 4, and is further preferably 4.
[0200] In the general formula (1), X.sup.1 represents a x valent
linking group consisting of a x valent hydrocarbon chain having 2
to 300 carbon atoms which may include an ether bond (--O--) and/or
an ester bond (--(C.dbd.O)--O--).
[0201] Here, in the general formula (1), a plurality (x) of the
thioxanthone structures (in the general formula (1) a structure
represented by [ ]) excluding X.sup.1 which is a linking group are
included, however, the thioxanthone structures may be the same as
or different from each other and are not particularly limited. From
the viewpoint of synthesis, they are preferably the same.
[0202] In the compound represented by the general formula (1), a
substituted position to thioxanthone is represented as described
below.
##STR00007##
[0203] A substituted position of X.sup.1 is 1 to 4-position,
2-position, 3-position or 4-position is preferable, 2-position or
4-position is more preferable, and 4-position is further
preferable.
[0204] A substituted position of R.sup.1 is 5 to 8-position,
6-position or 7-position is preferable, and 6-position is more
preferable.
[0205] In addition, a substituted position of R.sup.2 is 1 to
4-position, 1-position, 2-position or 3-position is preferable, and
1-position is more preferable.
[0206] The compound represented by the general formula (1) is
preferably a compound represented by the following general formula
(1').
##STR00008##
[0207] In the general formula (1'), R', R.sup.2, j and k are
respectively the same as R.sup.1, R.sup.2, j and k in the general
formula (1) and are also in the same as the preferred range.
[0208] In the general formula (1'), R.sup.11 is each independently
represents a hydrogen atom or an alkyl group having 1 to 4 carbon
atoms, a hydrogen atom, a methyl group or an ethyl group is
preferable, and a hydrogen atom is more preferable.
[0209] In the general formula (1'), r each independently represents
an integer of 1 to 6, is preferably an integer of 1 to 3, is more
preferably 1 or 2, and is further preferably 1. In addition, when
the value of r is 2 or more, R.sup.11s which is in multiple numbers
may be composed of the same or different groups.
[0210] x' represents an integer of 2 to 4, is preferably 2 or 3,
and is further preferably 2.
[0211] Y.sup.1 represents a residue in which the hydrogen atoms in
x of hydroxy groups are removed from a polyhydroxy compound having
at least x of hydroxyl groups, and a residue in which hydrogen
atoms in all (x) hydroxy groups are removed from a polyhydroxy
compound having x of hydroxyl groups is preferable. Specifically, a
residue in which hydrogen atoms in x of hydroxy groups are removed
from a polyhydroxy compound selected from a group consisting of
ethylene glycol, propylene glycol, butylene glycol, glycerin,
trimethylolpropane, ditrimethylolpropane and pentaerythritol is
preferable, in addition a residue in which hydrogen atoms in all
hydroxy groups are removed is preferable.
[0212] In the general formula (1'), A.sup.1 represents a group
selected from a group consisting of (i) to (iii) described
above.
[Chem. 9]
*--[O(CHR.sup.12CHR.sup.13).sub.a].sub.d--** (i)
*--[O(CH.sub.2).sub.bCO].sub.d--** (ii)
*--[O(CH.sub.2).sub.bCO].sub.(d-1)--[O(CHR.sup.12CHR.sup.13).sub.a]--**
(iii)
[0213] In the general formulae (i) to (iii), either one of R.sup.12
and R.sup.13 represents a hydrogen atom, the other represents a
hydrogen atom, a methyl group or an ethyl group, a represents an
integer of 1 or 2, b represents an integer of 4 or 5, and d
represents an integer of 1 to 20 Here, "*" indicates a bond
position with a carbonyl carbon and "**" indicates a bond position
with Y.sup.1.
[0214] A.sup.1 is preferably a group represented by the general
formula (i), and is more preferably
*--(OCH.sub.2CH.sub.2).sub.d--**,
*--(OCH.sub.2CH.sub.2CH.sub.2CH.sub.2).sub.d--**, or
*--O(CH(CH.sub.3)CH.sub.2).sub.d--**. In this case, d is more
preferably an integer of 3 to 10.
[0215] The molecular weight of the compound represented by the
general formula (1) is 1,000 or more. Among those, the molecular
weight is preferably from 1,000 to 3,000, more preferably from
1,000 to 2,500, and further preferably from 1,000 to 2,000.
[0216] If the molecular weight is less than 1,000, the elution from
the cured film is not suppressed and the odor properties also
deteriorate. In addition, if the molecular weight is 3,000 or less,
a steric hindrance in a molecule is small, furthermore, a degree of
freedom in a liquid/film of a molecule is maintained, and thus high
sensitivity is obtained.
[0217] Here, in a case where the sensitizer is used by mixing a
plurality of compounds from which the number of carbons or the like
is different, it is preferable that the weight average molecular
weight satisfy the range described above.
[0218] Hereinafter, specific examples of the compound represented
by the general formula (1) are shown, however, the present
invention is not limited to these compounds.
##STR00009## ##STR00010##
[0219] Among those, the compound (I-A) or (I-E) is preferable, and
the compound (I-E) is more preferable.
[0220] As the compound represented by the general formula (1),
commercially available compounds may be also used. Specifically,
Speedcure 7010
(1,3-di({.alpha.-[1-chloro-9-oxo-9H-thioxanthen-4-yl]oxy}acetylpoly[oxy(1-
-methylethylene)])oxy)-2,2-bis({.alpha.-[1-chloro-9-oxo-9H-thioxanthen-4-y-
l]oxy}acetylpoly[oxy(1-methyl ethyl ene)])oxy methyl)propane, CAS
No 1003567-83-6), and Omnipol TX (Polybutyleneglycol
bis(9-oxo-9H-thioxanthenyloxy)acetate, CAS No. 813452-37-8) are
exemplified.
[0221] The compound represented by the general formula (1) can be
manufactured by a well-known reaction. There is no particularly
limitation, however, for example, the compound represented by the
general formula (1') can be prepared by the compound represented by
the following general formula (1-1) reacting with the compound
represented by the following general formula (1-2).
##STR00011##
[0222] In the general formula (1-1) and the general formula (1-2),
R.sup.1, R.sup.2, R.sup.11, A.sup.1, Y.sup.1, j, k, r and x' are
the same as those in the general formula (1') and are also in the
same as the preferred range.
[0223] The reaction described above is preferably conducted in the
presence of a solvent, and as a suitable solvent, an aromatic
hydrocarbon such as benzene, toluene or xylene is exemplified.
[0224] In addition, the reaction is preferably conducted under the
catalytic, and as the catalyst, a sulfonic acid (for example,
p-toluenesulfonic acid and methanesulfonic acid), an inorganic acid
(for example, sulfuric acid, hydrochloric acid and phosphoric
acid), a Lewis acid (aluminum chloride, boron trifluoride and
organotitanate), and the like are exemplified.
[0225] The reaction temperature and the reaction time are not
particularly limited.
[0226] After the reaction is finished, a product can be separated
by isolating from a reaction mixture by well-known means, and
washing and drying, as necessary.
[0227] In addition, as the sensitizer, the compound represented by
the following general formula (2) is also a preferred compound.
##STR00012##
[0228] In the general formula (2), R.sup.3 and R.sup.4 each
independently represent an alkyl group having 1 to 5 carbon atoms
or a halogen atom, m represents an integer of 0 to 4, n represents
an integer of 0 to 3, y represents an integer of 2 to 4, and when m
and n are in integer of 2 or more, R.sup.3s and R.sup.4s which are
in multiple numbers may be composed of the same or different
groups, and X.sup.2 represents a y valent hydrocarbon chain having
2 to 300 carbon atoms which may include an ether bond and/or an
ester bond.
[0229] In the general formula (2), R.sup.3 and R.sup.4 each
independently represent an alkyl group having 1 to 5 carbon atoms
or a halogen atom.
[0230] The alkyl group having 1 to 5 carbon atoms may be any of
linear, branched or cyclic, however, linear or branched is
preferable, an alkyl group having 1 to 4 carbon atoms is
preferable, an alkyl group having 2 or 3 carbon atoms is more
preferable, and an ethyl group or an isopropyl group is further
preferable.
[0231] As the halogen atom, a fluorine atom, a chlorine atom, a
bromine atom and an iodine atom are exemplified and a chlorine atom
is preferable.
[0232] Among those, R.sup.3 and R.sup.4 are particularly preferably
an ethyl group, an isopropyl group or a chlorine atom.
[0233] In the general formula (2), m represents an integer of 0 to
4, is preferably 0 to 2, and is more preferably 0 or 1. In a case
where m is in integer of 2 or more, R.sup.3s which is in multiple
numbers may be composed of the same or different groups.
[0234] In the general formula (2), n represents an integer of 0 to
3, is preferably 0 to 2, is more preferably 0 or 1, and is further
preferably 0 In a case where n is in integer of 2 or more, R.sup.4s
which is in multiple numbers may be composed of the same or
different groups.
[0235] In the general formula (2), y represents an integer of 2 to
4, is more preferably 2 or 3, and is further preferably 2.
[0236] In the general formula (2), X.sup.2 represents a y valent
linking group consisting of a y valent hydrocarbon chain having 2
to 300 carbon atoms which may include an ether bond (--O--) and/or
an ester bond (--(C.dbd.O)--O--).
[0237] Here, in the general formula (2), a plurality (y) of the
benzophenone structures (in the general formula (2), a structure
represented by [ ]) excluding X.sup.2 which is a linking group are
included, however, the benzophenone structures may be the same as
or different from each other and are not particularly limited. From
the viewpoint of synthesis, they are preferably the same.
[0238] In the compound represented by the general formula (2), a
substituted position to benzophenone is represented as described
below.
##STR00013##
[0239] A substituted position of X.sup.2 is 1 to 4-position,
2-position, 3-position or 4-position is preferable, 2-position or
4-position is more preferable, and 4-position is further
preferable.
[0240] A substituted position of R.sup.3 is 5 to 8-position,
6-position or 7-position is preferable, and 6-position is more
preferable.
[0241] In addition, a substituted position of R.sup.4 is 1 to
4-position, 1-position, 2-position or 3-position is preferable, and
1-position is more preferable.
[0242] The compound represented by the general formula (2) is
preferably a compound represented by the following general formula
(2').
##STR00014##
[0243] In the general formula (2'), R.sup.3, R.sup.4, m and n are
respectively the same as R.sup.3, R.sup.4, m and n in the general
formula (2) and are also in the same as the preferred range.
[0244] In the general formula (2'), R.sup.21 is each independently
represents a hydrogen atom or an alkyl group having 1 to 4 carbon
atoms, a hydrogen atom, a methyl group or an ethyl group is
preferable, and a hydrogen atom is more preferable.
[0245] In the general formula (2'), t each independently represents
an integer of 1 to 6, is preferably an integer of 1 to 3, is more
preferably 1 or 2, and is further preferably 1. In addition, when
the value of t is 2 or more, R.sup.21s which is in multiple numbers
may be composed of the same or different groups.
[0246] y' represents an integer of 2 to 4, is preferably 2 or 3,
and is further preferably 2.
[0247] Y.sup.2 represents a residue in which the hydrogen atoms in
y's of the hydroxy groups are removed from a polyhydroxy compound
having at least y of the hydroxy groups, and a residue in which the
hydrogen atoms in all (y) hydroxy groups are removed from a
polyhydroxy compound having y of the hydroxy groups is preferable.
Specifically, a residue in which the hydrogen atoms in y of the
hydroxy groups are removed from a polyhydroxy compound selected
from a group consisting of ethylene glycol, propylene glycol,
butylene glycol, glycerin, trimethylolpropane, ditrimethylolpropane
and pentaerythritol is preferable, furthermore, a residue in which
the hydrogen atoms in all hydroxyl groups are removed is
preferable.
[0248] In the general formula (2'), A.sup.2 represents a group
selected from a group consisting of the following (i) to (iii).
[Chem. 16]
*--[O(CHR.sup.12CHR.sup.13).sub.a].sub.d--** (i)
*--[O(CH.sub.2).sub.bCO].sub.d--** (ii)
*--[O(CH.sub.2).sub.bCO].sub.(d-1)--[O(CHR.sup.12CHR.sup.13).sub.a]--**
(iii)
[0249] In the general formulae (i) to (iii), either one of R.sup.12
and R.sup.13 represents a hydrogen atom, the other represents a
hydrogen atom, a methyl group or an ethyl group a represents an
integer of 1 or 2, b represents an integer of 4 or 5, and d
represents an integer of 1 to 20. Here, "*" indicates a bond
position with a carbonyl carbon and "**" indicates a bond position
with Y'.
[0250] A.sup.2 is preferably a group represented by the general
formula (i), and is more preferably
*--(OCH.sub.2CH.sub.2).sub.d--**,
*--(OCH.sub.2CH.sub.2CH.sub.2CH.sub.2).sub.d--**, or
*--O(CH(CH.sub.3)CH.sub.2).sub.d--**. In this case, d is more
preferably an integer of 3 to 10.
[0251] The molecular weight of the compound represented by the
general formula (2) is 1,000 or more Among those, the molecular
weight is preferably from 1,000 to 3,000, more preferably from
1,000 to 2,500, and further preferably from 1,000 to 2,000.
[0252] If the molecular weight is 1,000 or more, the ink
composition in which the elution from the cured film is suppressed
and the odor properties and blocking are suppressed is obtained. In
addition, if the molecular weight is 3,000 or less, a steric
hindrance in a molecule is small, furthermore, a degree of freedom
in a liquid/film of a molecule is maintained, and thus high
sensitivity is obtained.
[0253] Here, in a case where the compound represented by the
general formula (2) is used as a mixture of a plurality of
compounds which have different number of carbons or the like, the
weight average molecular weight is preferably in the range
described above.
[0254] Hereinafter, specific examples of the compounds represented
by the general formula (2) are shown, however, the present
invention is not limited to these compounds.
##STR00015## ##STR00016##
[0255] As the compound represented by the general formula (2),
commercially available compounds can be also used. Specifically,
for example, Omnipol BP (Polybutyleneglycol
bis(4-benzoylphenoxy)acetate, CAS No. 515136-48-8) is
exemplified.
[0256] The compound represented by the general formula (2) can be
manufactured by a well-known reaction. The method of manufacturing
is not particularly limited, however, for example, the compound
represented by the general formula (2') can be prepared by the
compound represented by the following general formula (2-1)
reacting with the compound represented by the following general
formula (2-2).
##STR00017##
[0257] In the general formula (2-1) and the general formula (2-2),
R.sup.3, R.sup.4, R.sup.21, A.sup.2, Y.sup.2, m, n, t and y' are
the same as those in the general formula (2') and are also in the
same as the preferred range.
[0258] The reaction described above is preferably conducted in the
presence of a solvent. As a suitable solvent, an aromatic
hydrocarbon such as benzene, toluene or xylene is exemplified.
[0259] In addition, the reaction is preferably conducted under the
catalytic. As the catalytic, a sulfonic acid (for example,
p-toluenesulfonic acid and methanesulfonic acid), an inorganic acid
(for example, sulfuric acid, hydrochloric acid and phosphoric
acid), a Lewis acid (aluminum chloride, boron trifluoride and
organotitanate), and the like are exemplified.
[0260] The reaction time and the reaction temperature are not
particularly limited.
[0261] After the reaction is finished, a product can be separated
by isolating from a reaction mixture by well-known means, and
washing and drying, as necessary.
[0262] [Photopolymerization Initiator]
[0263] The actinic ray curable ink composition in the present
invention preferably includes a photopolymerization initiator. The
photopolymerization initiator can be appropriately selected from
the compounds which are able to initiate the polymerization
reaction of the polymerizable compound by an actinic energy ray. As
an example of the polymerization initiator, a photopolymerization
initiator which generates an active species (radical, acid, basic,
or the like) by an actinic ray such as radiation or light is
included.
[0264] As an example of the photopolymerization initiator,
acetophenone, 2,2-diethoxy acetophenone,
p-dimethylaminoacetophenone, p-dimethylaminopropiophenone,
benzophenone, 2-chlorobenzophenone, p,p'-dichlorobenzofen,
p,p'-bisdiethylaminobenzophenone, Michler's ketone, benzil,
benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin
isopropyl ether, benzoin n-propyl ether, benzoin isobutyl ether,
benzoin n-butyl ether, benzyl dimethyl ketal, tetramethyl thiuram
monosulfide, thioxanthone, 2-chlorothioxanthone,
2-methylthioxanthone, azobisisobutyronitrile, benzoin peroxide,
di-tert-butyl peroxide, 1-hydroxycyclohexyl phenyl ketone,
1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one,
2-hydroxy-2-methyl-1-phenyl-1-one,
1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, methyl
benzoyl formate are included. Furthermore, for example, an aromatic
diazonium salt, an aromatic halonium salt, an aromatic sulfonium
salt, a metallocene compound, and the like such as triphenyl
sulfonium hexafluorophosphate, diphenyl iodonium
hexafluoroantimonate are included.
[0265] Other than the above, a bisacylphosphine oxide compound and
an .alpha.-aminoketone compound are suitably included.
[0266] The bisacylphosphine oxide compound is not particularly
limited, and a well-known compound can be used, however, the
compound represented by the following general formula (b-1) is
preferable. The compound is may be used either alone or as a
combination of two or more.
##STR00018##
[0267] In the general formula (b-1), R.sup.1E, R.sup.2E and
R.sup.3E each independently represent an aromatic hydrocarbon group
which may contain a halogen atom, a methyl group or an ethyl group
as a substituent.
[0268] Among the well-known bisacylphosphine oxide compounds, for
example, the bisacylphosphine oxide compounds disclosed in
JP1991-101686A (JP-H03-101686A), JP1993-345790A (JP-H05-345790A),
and JP1994-298818A (JP-H06-298818A) are included.
[0269] As specific examples,
bis(2,6-dichlorobenzoyl)phenylphosphine oxide,
bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide,
bis(2,6-dichlorobenzoyl)-4-ethoxyphenylphosphine oxide,
bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide,
bis(2,6-dichlorobenzoyl)-2-naphthylphosphine oxide,
bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide,
bis(2,6-dichlorobenzoyl)-4-chlorophenylphosphine oxide,
bis(2,6-dichlorobenzoyl)-2,4-dimethoxyphenylphosphine oxide,
bis(2,6-dichlorobenzoyl)decylphosphine oxide,
bis(2,6-dichlorobenzoyl)-4-octylphenylphosphine oxide,
bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide,
bis(2,4,6-trimethylbenzoyl)-2,5-dimethylphenylphosphine oxide,
bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-2,5-dimethylphenylphosphine
oxide,
bis(2,6-dichloro-3,4,5-trimethoxybenzoyl)-4-ethoxyphenylphosphine
oxide, bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide,
bis(2-methyl-1-naphthoyl)-4-ethoxyphenylphosphine oxide,
bis(2-methyl-1-naphthoyl)-2-naphthylphosphine oxide,
bis(2-methyl-1-naphthoyl)-4-propylphenylphosphine oxide,
bis(2-methyl-1-naphthoyl)-2,5-dimethylphenylphosphine oxide,
bis(2-methoxy-1-naphthoyl)-4-ethoxyphenylphosphine oxide,
bis(2-chloro-1-naphthoyl)-2,5-dimethylphenylphosphine oxide,
bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and
the like are included.
[0270] Among those, bis(2,4,6-trimethylbenzoyl)phenylphosphine
oxide (IRGACURE 819, manufactured by BASF Japan Ltd.) and
bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphenylphosphine
oxide are preferable, and
bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide is particularly
preferable.
[0271] The .alpha.-aminoketone compound is not particularly
limited, and the well-known compounds can be used. Among those, the
compound represented by the following general formula (b-2) is
preferable. The .alpha.-aminoketone compound is may be used either
alone or as a combination of two or more.
##STR00019##
[0272] In the general formula (b-2), Ar represents a phenyl group
which is substituted with --SR.sup.5H or --N(R.sup.7H)(R.sup.8H),
R.sup.5H represents a hydrogen atom or an alkyl group, R.sup.1H and
R.sup.2H each independently represent an alkyl group having 1 to 8
carbon atoms, and R.sup.3H and R.sup.4H each independently
represent a hydrogen atom, an alkyl group having 1 to 12 carbon
atoms, an alkyl group having 2 to 4 carbon atoms which is
substituted with an alkoxy having 1 to 4 carbon atoms or an alkenyl
group having 3 to 5 carbon atoms. R.sup.1H and R.sup.2H may be
bonded to each other to configure an alkylene group having 2 to 9
carbon atoms. R.sup.3H and R.sup.4H may be bonded to each other to
form an alkylene group having 3 to 7 carbon atoms, and the alkylene
group may contain --O-- or --N(R.sup.6H)-- in an alkylene chain.
R.sup.6H represents an alkyl group having 1 to 4 carbon atoms.
R.sup.7H and R.sup.8H each independently represent a hydrogen atom,
an alkyl group having 1 to 12 carbon atoms, an alkyl group having 2
to 4 carbon atoms which is substituted with an alkoxy having 1 to 4
carbon atoms or an alkenyl group having 3 to 5 carbon atoms.
R.sup.7H and R.sup.8H may be bonded to each other to form an
alkylene group having 3 to 7 carbon atoms, and the alkylene group
may contain --O-- or --N(R.sup.6H)-- in an alkylene chain. Here,
R.sup.6H is the same as that described above.
[0273] As an example of the .alpha.-aminoketone compound,
2-benzyl-2-dimethyl-1-(4-morpholinophenyl)-butanone-1 (Irgacure
369, manufactured by BASF Japan Ltd.) and
2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-on-
e (Irgacure 379) are included.
[0274] In addition, the .alpha.-aminoketone compound having high
molecular weight is also preferable. Specifically, polyethylene
glycol
di{.beta.-4-[4-(2-dimethylamino-2-benzyl)butanoylphenyl]piperazine}
(Omnipol 910, the average molecular weight: 1032, manufactured by
Insight High Technology Co., Ltd.) is included.
[0275] In a case of including the photopolymerization initiator,
the content of the photopolymerization initiator in the ink
composition is preferably from 0.5% by mass to 10% by mass, and
more preferably from 1% by mass to 6% by mass, with respect to the
total ink composition.
[0276] [Resin Component]
[0277] The actinic ray curable ink composition in the present
invention may include a resin component.
[0278] As an example of the resin component, an acrylic based
polymer, a polyvinyl butylal resin, a polyurethane resin, a
polyamide resin, a polyester resin, an epoxy resin, a phenolic
resin, a polycarbonate resin, a polyvinyl butyral resin, a
polyvinyl formal resin, a shellac, a vinyl based resin, an acrylic
based resin, a rubber based resin, waxes, other natural resins, and
the like are included. Among those, a vinyl based copolymer which
is obtained by the copolymerization of an acryl based monomer is
preferable. Furthermore, as the copolymerization composition of the
high molecular compound, a carboxyl group containing monomer, a
methacrylic acid alkyl ester, and/or a copolymer which includes a
acrylic acid alkyl ester as a monomer unit are also preferably
used.
[0279] The resin component is may be used either alone or as a
combination of two or more.
[0280] In a case where the ink composition in the present invention
includes the resin component, the content of the resin component is
preferably from 0.5% by mass to 20% by mass, and more preferably
from 1% by mass to 10% by mass, with respect to the total ink
composition.
[0281] [Other Components]
[0282] The actinic ray curable ink composition in the present
invention can be configured by further using other components in
addition to the components described above.
[0283] Other components include an ultraviolet absorber, an
antioxidant, an antifading agent, conductive salts, solvents, a
high molecular weight compound, a basic compound, and the like and
can be appropriately selected from well-known ones. For example,
the components described in JP2009-221416A are included.
[0284] In addition, the ink composition in the present invention
preferably includes a polymerization inhibitor, from the viewpoint
of the storage stability and the suppression of head clogging.
[0285] As a polymerization inhibitor, a nitroso based
polymerization inhibitor, a hindered amine based polymerization
inhibitor, hydroquinone, benzoquinone, p-methoxyphenol, TEMPO,
TEMPOL, cupferron A1, and the like are included. The content of the
polymerization inhibitor is preferably from 200 ppm to 20,000 ppm,
with respect to the total mass of the ink composition in the
present invention.
[0286] --Curing Step--
[0287] In the curing step in the present invention, the image is
cured by irradiating with an actinic ray under the conditions in
which the oxygen partial pressure is 1.5.times.10.sup.-2 MPa or
less with respect to the image which is formed in the image forming
step described before.
[0288] The reason is that the polymerization initiator which is
included in the ink composition of the present invention is
decomposed by irradiation with an actinic ray, an polymerization
initiation species such as radical is generated, and the
polymerization reaction of the polymerizable compound occurs and is
promoted by the function of the initiation species. At this time,
when the sensitizer is present in the ink composition, the
sensitizer in a system becomes an excited state by absorbing an
actinic ray, and the decomposition of the polymerization initiator
is preferably promoted by coming into contact with the
polymerization initiator, therefore the curing reaction can be
progressed with even higher sensitivity.
[0289] As an active ray, an .alpha. ray, a .gamma. ray, an electron
beam, an X ray, an ultraviolet ray, visible light, infrared light,
and the like are suitable. Depending on the absorption
characteristics of the sensitizer, for example, a peak wavelength
of an active ray is preferably from 200 nm to 600 nm, more
preferably from 300 nm to 450 nm, further preferably from 320 nm to
420 nm, and it is particularly preferred that an active ray be an
ultraviolet ray in which a peak wavelength is from 340 nm to 400
nm.
[0290] In addition, the illumination of the exposed surface of the
ink composition in the present invention is preferably from 10
mW/cm.sup.2 to 4,000 mW/cm.sup.2, and more preferably from 20
mW/cm.sup.2 to 2,500 mW/cm.sup.2.
[0291] As an actinic ray source, a mercury lamp, a gas or solid
laser, and the like are mainly used, and as a light source which is
used for curing the ink composition for ultraviolet ray photo
curable type inkjet recording, a mercury lamp and a metal halide
lamp are widely known. However, mercury-free is currently strongly
desired, from the viewpoint of the environmental protection, and it
is very useful industrially and environmentally to replace with a
GaN based semiconductor ultraviolet light emitting device.
Furthermore, an LED (UV-LED) and an LD (UV-LD) are of small-size,
long-life, high efficiency and low cost, and are expected as a
light source for photo curable type inkjet.
[0292] In addition, a light-emitting diode (LED) and a laser diode
(LD) can be used as an active ray source. In particular, in a case
where an ultraviolet ray source is required, an ultraviolet LED and
an ultraviolet LD can be used. For example, NICHIA CORPORATION puts
an ultraviolet LED in which the main emission spectrum has a
wavelength between 365 nm and 420 nm on the market. In a case where
an even shorter wavelength is required, an LED which is centered
between 300 nm and 370 nm and can emit an actinic ray is disclosed
in U.S. Pat. No. 6,084,250A. In addition, other ultraviolet LEDs
are also available, and it is possible to irradiate with radiation
in a different ultraviolet band. Particularly preferred actinic ray
source in the present invention is an UV-LED, and an UV-LED having
a peak wavelength from 340 nm to 400 nm is particularly
preferable.
[0293] Here, the maximum luminance on a recording medium of an LED
is preferably from 10 mW/cm.sup.2 to 2,000 mW/cm.sup.2, more
preferably from 20 mW/cm.sup.2 to 1,000 mW/cm.sup.2, and
particularly preferably from 50 mW/cm.sup.2 to 800 mW/cm.sup.2.
[0294] It is suitable for the ink composition in the present
invention to be irradiated with such an actinic energy ray for
preferably 0.01 seconds to 120 seconds, and for more preferably 0.
1 second to 90 seconds.
[0295] Irradiation conditions and a basic irradiation method of an
actinic energy ray are disclosed in JP1985-132767A
(JP-S60-132767A). Specifically, the light sources are provided on
both sides of a head unit including a discharge device of the ink
composition, and the irradiation is performed by scanning the head
unit and the light source by a so-called shuttle method. After the
ink composition is landed, the irradiation with an actinic energy
ray is performed for a certain time (preferably from 0.01 seconds
to 0.5 seconds, more preferably from 0.01 seconds to 0.3 seconds,
and further preferably from 0.01 seconds to 0.15 seconds). In this
manner, by controlling the time from landing to irradiating of the
ink composition to a very short time, it becomes possible to
prevent bleeding of the ink composition landed on the recording
medium before curing. In addition, since it is also possible to
exposure with respect to the porous recording medium before the ink
composition permeates until the deep part in which the light source
does not reach, it is possible to suppress the residues of the
unreacted monomer, which is therefore preferable.
[0296] Furthermore, the curing may be completed by other light
source unaccompanied by a driving. As an irradiation method, for
example, a method of using an optical fiber or a method of
irradiating a recording unit with UV light by lighting up a mirror
surface which is arranged on the side of a head unit by using a
collimated light source as described in WO99/54415A can be also
applied.
[0297] In addition, in the present invention, when irradiating with
an actinic ray, an atmosphere around the surface of the medium to
be recorded is set to a poor oxygen atmosphere. It is well known
that it is possible to decrease energy of an actinic ray which is
required for curing by suppressing the oxygen concentration in an
atmosphere while curing, however, in the present invention, the
elution amount of an unreacted monomer, or the like from the formed
image is suppressed, and an improvement in the odor properties is
also achieved.
[0298] Generally, in a radical polymerization based ink
composition, the surface which comes into contact with the air is
particularly easily subjected to the inhibition of polymerization
by oxygen, and in particular, the insufficient curing of the
surface easily occurs. The monomer remains in the film due to the
insufficient curing of the surface and the performance of holding
the low molecular weight components in the film becomes
insufficient due to forming the crosslinked structure of the film
by the polyfunctional monomer, therefore, the elution from the
image and the odor significantly deteriorate. In the present
invention, since a degree of the inhibition of polymerization by
oxygen is reduced and the elution amount of the unreacted monomer
or the like is suppressed by expositing under an environment in
which the oxygen concentration is low, it is presumed that the odor
is improved.
[0299] In the present invention, the irradiation with an actinic
ray is performed under a poor oxygen atmosphere in which the oxygen
partial pressure is 1.5.times.10.sup.-2 MPa or less. Details
thereof are as described below.
[0300] Since the partial pressure of oxygen is usually
2.1.times.10.sup.-2 MPa (atmospheric pressure) under the
atmospheric air (one atmospheric pressure), in order to reduce the
partial pressure of oxygen to 1.5.times.10.sup.-2 MPa or less, it
is possible to achieve by (a) reducing the atmospheric air when
exposing to set to 0.71 atmospheric pressure or less, or (b) mixing
air with 40% by volume or more of gas, except oxygen (for example,
an inert gas such as nitrogen or argon), with respect to the
air.
[0301] The poor oxygen atmosphere in the present invention is not
particularly limited, and any method described above can be
used.
[0302] The oxygen partial pressure is 1.5.times.10.sup.-2 MPa or
less, preferably 1.0.times.10.sup.-2 MPa or less, more preferably
0.8.times.10.sup.-2 MPa or less, and particularly preferably
0.5.times.10.sup.-2 MPa or less. The lower limit of the oxygen
partial pressure is not particularly limited. By evacuating or
replacing the atmosphere with gas (for example, nitrogen) except
air, it is possible to virtually set the oxygen partial pressure to
0, which is also a preferred method.
[0303] The oxygen concentration by the inert gas replacement is
preferably controlled to 0.1% to 15% (at this time, the oxygen
partial pressure is from 0.1.times.10.sup.-2 MPa to
1.5.times.10.sup.-2 MPa (from 0.001 atm to 0.15 atm), and more
preferably controlled to 0.1% to 10%.
[0304] As means of controlling the oxygen concentration of the
atmosphere while curing to 0.1% to 15%, for example, there are
methods of setting to the nitrogen atmosphere or the carbon dioxide
atmosphere by setting an image forming device to a closed system,
and the like. As means of supplying nitrogen, for example, there
are methods of using a nitrogen gas cylinder or using a device in
which only nitrogen gas is separated from the air using the
difference of the permeability between oxygen and nitrogen to the
hollow fiber membrane. As means of supplying carbon dioxide, there
is also a method of supplying using a gas cylinder.
[0305] An inert gas means general gases such as N.sub.2, H.sub.2 or
CO.sub.2, or rare gases such as He, Ne or Ar. Among these, N.sub.2
is suitably used from the reasons of the safety and availability,
and the problem of cost.
[0306] Under the reduced pressure means a state which is 500 hPa
(0.05 MPa) or less, and preferably 100 hPa (0.01 MPa) or less.
[0307] <Inkjet Recording Device>
[0308] An inkjet recording device in the present invention is
configured by including transporting means for transporting the
inkjet head which discharges an actinic ray curable ink composition
containing a pigment, a polyfunctional polymerizable compound in
which the content ratio to the total polymerization component is
80% by mass or more and a sensitizer in which the molecular weight
is 1,000 or more with the amount of ink droplets of 25 pl to 200 pl
and a recording substrate with a long shape which is an aggregate
of a nonabsorbable or a low absorbable fiber material while the
distance between the recording substrate and the inkjet head is set
to from 5 mm to 20 mm, and first irradiating means for irradiating
with respect to the image which is formed by the actinic ray
curable ink composition which is discharged from the inkjet head
with an actinic ray under the conditions in which the oxygen
partial pressure is 1.5.times.10.sup.-2 MPa or less. Details of the
actinic ray curable ink composition are as described before.
[0309] The inkjet recording device of the present invention may be
configured by further including other configurations such as a
pinning light source for performing the temporary exposure (the
pinning exposure) for preventing landing interference, as
necessary.
[0310] As the inkjet recording device which can be used in the
present invention, for example, a device having an ink supply
system, a temperature sensor, an actinic energy ray source is
included.
[0311] The ink supplying system, for example, may be configured by
providing with an ink tank accumulating the ink composition in the
present invention, an ink supply tube, an ink supply tank right
before the inkjet head, a filter, and a piezo type inkjet head.
[0312] The inkjet method of forming the image using the inkjet head
is not particularly limited, however, a drop-on-demand method (a
pressure pulse method) using vibration pressure of a piezo element
is preferably used. Here, the inkjet method includes a method of
discharging low concentration ink known as photo ink in a small
volume many times, a method of improving the image quality using a
plurality of inks of different concentrations with substantially
the same hue, and a method of using colorless transparent ink.
[0313] The inkjet head is preferably an inkjet head which can
discharge the actinic ray curable ink composition with the amount
of ink droplets of 75 pl or more, from the viewpoint of forming the
image on the recording substrate such as a nonwoven fabric. Among
those, as the amount of ink droplets, from 75 pl to 200 pl is
further preferable.
[0314] As the inkjet head, a line head in which a plurality of
nozzle holes (recording elements) are two-dimensionally arrayed is
suitable, and as the nozzle density thereof, from 50 npi to 400 npi
is preferable, from 30 npi to 300 npi is more preferable, and from
50 npi to 200 npi is further preferable, from the viewpoint of not
generating a void in a solid and reducing drying load. If the
nozzle density is smaller than 50 npi, a void is easily generated
in a solid part. If the nozzle density is bigger than 400 npi, the
amount of the ink which is imparted onto the fiber material becomes
too much, and thus the drying load increases.
[0315] The inkjet recording device is preferably provided with
stabilization means for stabilizing the temperature of the ink
composition. The parts which are maintained at a certain
temperature are subject to the piping system from the ink tank (an
intermediate tank in a case where there is an intermediate tank) up
to a nozzle emission surface of the inkjet head and all members.
That is, it is possible to insulate and heat from the ink supply
tank up to the inkjet head part.
[0316] A method of controlling the temperature is not particularly
restricted; however, for example, it is preferable to provide a
plurality of the temperature sensors on each piping part and
perform a heating control in accordance with the flow rate of the
ink composition and the environmental temperature. The temperature
sensors can be provided in the vicinity of the ink supply tank and
the nozzle of the inkjet head. In addition, it is preferable that
the head unit to be heated be thermally interrupted or insulated so
that the device body is not affected by the temperature from the
outside air. In order to shorten the startup time of a printer
required for heating, or in order to reduce heat energy loss, it is
preferable to insulate from other parts and decrease the heat
capacity of the entire heating unit.
[0317] As a whole, since the actinic ray curable ink composition
has higher viscosity when compared with the aqueous ink which is
usually used for an application of an inkjet recording, the
viscosity fluctuation due to the temperature fluctuation when
discharging is large. The viscosity fluctuation of the ink
composition has a considerable effect on the change of the size of
droplets and the change of the discharge speed of droplets,
eventually, influences the formation properties of the image
quality. Therefore, it is important to retain the temperature of
the ink composition when discharging constant as much as possible.
As the control band of the temperature of the ink composition,
.+-.5.degree. C. of the preset temperature is preferable,
.+-.2.degree. C. of the preset temperature is more preferable, and
.+-.1.degree. C. of the preset temperature is further
preferable.
[0318] Hereinafter, an example of an inkjet recording device for
suitably conducting the inkjet recording method of the present
invention is specifically explained in reference to FIG. 1. FIG. 1
is a schematic configuration diagram illustrating a configuration
example of the entire inkjet recording device.
[0319] As shown in FIG. 1, in the inkjet recording device, an
inkjet head unit 7 provided with the inkjet head which serially
discharges various ink compositions toward the transport direction
(the direction of arrow in FIG. 1) of the recoding medium, a inert
gas blanket 2 which is an irradiation chamber provided with an LED
light source unit 1 as an example of first irradiating means, and
an inert gas generating device 4 which is an example of inert gas
supplying means are disposed. In addition, a transport stage 10
which transports the recording substrate is provided in a position
facing to the inkjet head unit 7 and the inert gas blanket 2. In
the upper stream of the substrate transport direction of the
transport stage, a wind-up roll 5a in which the recording substrate
with a long shape is winded is disposed, and in the lower stream of
the substrate transport direction of the transport stage, a wind-up
roll 5b which winds the recording substrate on which the image is
formed is installed.
[0320] A recording substrate 6 is supplied to the transport stage
10 from the wind-up roll 5a, passes through the inkjet head unit 7,
is sent to the inert gas blanket 2 in order, and is finally winded
at the wind-up roll 5b while transporting at a predetermined
transport speed on the transport stage. Here, a form of winding
once after forming the image is shown, however, a process such as
cutting may be conducted without winding, and, for example, a
recording substrate 6 may be finally accumulated or the like as a
record of sheet-like or the like.
[0321] The recording substrate 6 is stretched to be laid between
the wind-up roll 5a and 5b which are transport means. Out of two
wind-up rolls, at least one roller can be set to a driven roller in
which the power of the motor (not shown) is transmitted. By
rotating the driven roller with a constant rate which rotates by
the motor, it is possible to transport the recording substrate in a
predetermined direction at a predetermined transport speed.
[0322] As the transport speed of transporting the recording
substrate, 50 m/min or more is preferable, 100 m/min or more is
more preferable, and 200 m/min or more is further preferable.
[0323] A transport method may be also employed or used a belt
transport method, a stage transport method using stage or the like
together, in addition to using the rotational movement of the
wind-up roll 5a and 5b.
[0324] In the inkjet head unit 7 in which the inkjet heads which
discharge the ink compositions of each color are disposed, the ink
compositions of each color (K: black, Y: yellow, M: magenta, C:
cyan) are discharged. In the inkjet head unit 7, an inkjet head 7C
for cyan ink, an inkjet head 7M for magenta ink, an inkjet head 7Y
for yellow ink and an inkjet head 7K for black ink are serially
arranged along the substrate transport direction so as to be
capable of discharging the inks of four colors.
[0325] In addition, each inkjet head is fixed on a blanket which
can be expanded or contracted so that the distance to the recording
substrate (the distance L in a perpendicular direction in FIGURE)
can be adjusted. According to this, the distance L between the
inkjet head and the recording substrate can be appropriately
changed in accordance with the kind of the recording substrate or
the transport speed.
[0326] In the present device, the installed number of the inkjet
heads is changeable, and 1 to 6 heads can be installed.
[0327] In addition, a pinning source light source 8 for performing
the pre-exposure (the pinning exposure) and pre-curing the inks
which are respectively discharged in the upper stream side is
disposed between two inkjet heads disposed in the inkjet head unit
7 as second irradiating means. As the light source, the same ones
as the following actinic ray source can be appropriately selected
and used.
[0328] A light source unit 1 which emits the desired peak
wavelength (for example, 385 nm) is installed inside of the inert
gas blanket 2 which is an example of the irradiation chamber
disposed in the lower stream of the substrate transport direction
(the direction of the arrow) of the inkjet head unit 7 as an
actinic ray source. The recording substrate on which the image is
formed is carried into the irradiation chamber to form a zone for
irradiating the image with light. The light source unit 1 is
arranged as if being warped by the inert gas blanket 2.
[0329] The inert gas blanket 2 is connected to the inert gas
generating device 4 through the gas supply pipe 3.
[0330] As the actinic ray source, a mercury lamp, a gas or solid
laser, and the like are mainly used, and as the light source which
is used for curing the ink composition for ultraviolet ray photo
curable type inkjet recording, a mercury lamp and a metal halide
lamp are widely known. However, mercury-free is currently strongly
desired, from the viewpoint of the environmental protection, and it
is very useful industrially and environmentally to replace with a
GaN based semiconductor ultraviolet light emitting device.
Furthermore, an LED (UV-LED) and an LD (UV-LD) are of small-size,
long-life, high efficiency, and low cost, and are expected to be a
light source for photo curable type inkjet.
[0331] The inert gas generating device 4 which is means for setting
the atmosphere in the blanket 2 to the poor oxygen atmosphere can
supply the inert gas into the inside of the blanket 2 through the
gas supply pipe 3. In an initial state, the atmosphere in the
blanket 2 is the air, however, by starting and operating the inert
gas generating device 4, the inert gas is introduced into the
blanket 2 and by replacing the air in the blanket 2 into inert gas,
the low oxygen atmosphere (the oxygen partial
pressure.ltoreq.1.5.times.10.sup.-2 MPa) is formed. As inert gas,
nitrogen gas is suitably used.
[0332] The wind-up roll 5b installed in the further lower stream of
the inert gas blanket 2 in the substrate transport direction (the
direction of the arrow) can wind the recording substrate 6 carried
out from the transport stage which the image has been formed.
Example
[0333] Hereinafter, the present invention will be even more
specifically explained by Examples, however, the present invention
is not limited to the following Examples as long as it does not
exceed the gist thereof.
[0334] <Preparation of Mill Base>
[0335] --1. Preparation of Cyan Mill Base A--
[0336] 300 parts by mass of IRGALITE BLUE GLVO (manufactured by
BASF Japan Ltd.: cyan pigment), 590 parts by mass of SR9003
(Propylene oxide (PO) modified neopentyl glycol diacrylate,
manufactured by Sartomer Co. Inc.; bifunctional polymerizable
compound) and 100 parts by mass of SOLSPERSE 32000 (manufactured by
Noveon; dispersing agent) were stirred and mixed to prepare a cyan
mill base A.
[0337] Here, in the preparation of the cyan mill base A, each
component was placed into a disperser motor mill M50 (manufactured
by Eiger Corp.), and dispersion was performed for 4 hours at a
cycle speed of 9 m/s using zirconia beads of 0.65 mm diameter.
[0338] --2. Preparation of Magenta Mill Base B--
[0339] 300 parts by mass of CINQUASIA MAGENTA RT-355-D
(manufactured by BASF Japan Ltd.; magenta pigment), 1035 parts by
mass of R341 (3-methyl-1,5-pentanediol diacrylate, manufactured by
Sartomer Co. Inc.; bifunctional polymerizable monomer), and 150
parts by mass of EFKA7701 (manufactured by BASF Japan Ltd.;
dispersing agent) were stirred and mixed to prepare a magenta mill
base B.
[0340] Here, in the preparation of the magenta mill base B, each
component was placed into a disperser motor mill M50 (manufactured
by Eiger Corp.), and dispersion was performed for 4 hours at a
cycle speed of 9 m/s using zirconia beads of 0.65 mm diameter.
[0341] --3. Preparation of Yellow Mill Base C--
[0342] 300 parts by mass of NOVOPERM YELLOW H2G (manufactured by
Clariant; yellow pigment), 1035 parts by mass of SR341
(3-methyl-1,5-pentanediol diacrylate manufactured by Sartomer Co.
Inc.; bifunctional polymerizable monomer), and 150 parts by mass of
EFKA7701 (manufactured by BASF Japan Ltd.; dispersing agent) were
stirred and mixed to prepare a yellow mill base C.
[0343] Here, in the preparation of the yellow mill base C, each
component was placed into a disperser motor mill M50 (manufactured
by Eiger Corp.), and dispersion was performed for 4 hours at a
cycle speed of 9 m/s using zirconia beads of 0.65 mm diameter.
[0344] --4. Preparation of Black Mill Base D--
[0345] 300 parts by mass of SPECIAL BLACK 250 (manufactured by BASF
Japan Ltd.; black pigment), 370 parts by mass of SR9003 (PO
modified neopentyl glycol diacrylate, manufactured by Sartomer Co.
Inc.; bifunctional polymerizable compound) and 75 parts by mass of
SOLSPERSE 32000 (manufactured by Noveon; dispersing agent) were
stirred and mixed to prepare a black mill base D.
[0346] Here, in the preparation of the black mill base D, each
component was placed into a disperser motor mill M50 (manufactured
by Eiger Corp.), and dispersion was performed for 4 hours at a
cycle speed of 9 m/s using zirconia beads of 0.65 mm diameter.
[0347] <Preparation of Ink>
[0348] By mixing and stirring each component (unit: part by mass)
in compositions shown in Table 1 describe below, 1,000 g of a cyan
ink C-1, a magenta ink M-1, a yellow ink Y-1 and a black ink K-1
were respectively prepared. In all inks of four colors, the content
ratio of the polymerizable compound of bifunction or more
accounting for the total polymerization component contained in each
ink is 100% by mass. Stirring is performed at room temperature
under the conditions of the number of revolution: 5,000
revolution/min and stirring time: 20 minutes using a mixer (L4R,
manufactured by Silverson Nippon Ltd.).
[0349] Here, the viscosity (mPas) in Table 1 was measured under the
conditions of 25.degree. C. using VISCOMETER TV-22LT (manufactured
by TOKI SANGYOCO. LTD.). In addition, the surface tension (mN/m)
was measured under the conditions of 25.degree. C. using AUTOMATIC
SURFACE TENSIOMETER CBVP-Z (manufactured by Kyowa Interface Science
Co., LTD.).
TABLE-US-00001 TABLE 1 C-1 M-1 Y-1 K-1 Mill base Cyan mill base A
9.5 Magenta mill base B 16.4 Yellow mill base C 10.5 Black mill
base D 6 Monomer SR341 74.14 76.34 74.14 74.14 SR350 10 1.5 9 13.5
Initiator IRGACURE 819 4 4 4 4 Sensitizer Speedcure 7010 2 1.4 2 2
Polymeriza- FIRSTCURE ST-1 0.26 0.26 0.26 0.26 tion inhibitor
Surfactant BYK-307 0.1 0.1 0.1 0.1 Total 100 100 100 100 Viscosity
12 12 12 12 Surface 25 25 25 25 tension
[0350] Detailed description of components described in Table 1 is
shown as below.
[0351] SR341 (3-methyl-1,5-pentanediol diacrylate, manufactured by
Sartomer Co. Inc.; polymerizable compound)
[0352] SR350 (trimethylolpropane triacrylate, manufactured by
Sartomer Co. Inc.; polymerizable compound)
[0353] IRGACURE 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine
oxide, manufactured by BASF Japan Ltd., the molecular weight 418;
photopolymerization initiator)
[0354] Speedcure 7010 (compound I-B, manufactured by Lambson Ltd.,
the molecular weight 1988; sensitizer represented by the general
formula (1) described before)
[0355] FIRSTCURE ST-1 (a mixture of
tris(N-nitroso-N-phenylhydroxylamine)aluminum salt (10% by mass)
and phenoxyethylacrylate (90% by mass), manufactured by Chem First;
polymerization inhibitor)
[0356] BYK307 (silicone-based surfactant, manufactured by
BYK-Chemie Japan KK; surfactant)
[0357] <Preparation of Recording Substrate>
[0358] A polypropylene (PP) nonwoven fabric (the fiber surface
density: 30 g/m.sup.2, the thickness: 13 .mu.m, the fiber diameter:
20 .mu.m) was prepared and one in which Corona treatment was
performed twice under the conditions of the treatment voltage: 14
kV, and the treatment speed: 50 mm/s using Corona master
(manufactured by Shinko Electric & Instrumentation Co., Ltd.,
PS-10S), with respect to the PP nonwoven fabric was used as a
recording substrate.
[0359] <Preparation of Image Forming Device>
[0360] The inkjet recording device having a configuration shown in
Table 1 was produced and four inks which were prepared as above
were filled into the device.
[0361] In an inkjet drawing device produced in present example, as
shown in FIG. 1, the wind-up roll 5a in which a web-like
polypropylene (PP) nonwoven fabric is winded is installed, and as
the recording substrate on which the image is formed, the PP
nonwoven fabric 6 is sent to the transport stage 10. The PP
nonwoven fabric 6 is transported on the transport stage 10 while
being winded by the wind-up roll 5b capable of driving. In the
lower stream of the substrate transport direction of the wind-up
roll 5a, an inkjet head 7C for cyan ink, an inkjet head 7M for
magenta ink, an inkjet head 7Y for yellow ink and an inkjet head 7K
for black ink (all are the inkjet head QE 30 manufactured by
FUJIFILM Dimatix, Inc., (100 npi (nozzle/inch), capable of
discharging 30 pl of ink droplets)) are serially arranged along the
substrate transport direction so as to be capable of discharging
the inks of four colors. The inkjet head unit 7 in FIG. 1 is
configured by four inkjet heads 7C, 7M, 7Y and 7K. Each inkjet head
is fixed on a blanket which can be expanded or contracted so that
the distance to the recording substrate (the distance in a
perpendicular direction in FIGURE) can be adjusted and the distance
L between the inkjet head and the recording substrate can be
appropriately changed in accordance with the kind of the recording
substrate or the transport speed. Here, in the device, the
installed number of the heads is changeable, and 1 to 6 heads can
be installed.
[0362] In addition, the pinning source light source 8
(H-140WLH4-V2-FF1, manufactured by HOYA CANDEO OPTRONICS
CORPORATION; second irradiating means) for pre-curing the ink which
are discharged in the upper stream side is disposed between each
inkjet head (in Examples, a total number of 3 were disposed.)
[0363] In the lower stream of the substrate transport direction
(the direction of the arrow) of the inkjet head unit 7, the inert
gas blanket 2 which is an example of the irradiation chamber for
irradiating the image with ultraviolet light after the recording
substrate on which the image has been formed is installed is
disposed and an LED light source unit (LEDZero Solidcure,
manufactured by Integration Technology) 1 having a peak wavelength
of 385 nm is installed in the inert gas blanket 2. In addition, the
inert gas blanket 2 is connected with N.sub.2 gas generating device
with a compressor (Maxi-Flow 30, manufactured by In house Gas Ltd.)
through the gas supply pipe 3 as an inert gas source which is an
example of inert gas supplying means. At this time, the inert gas
blanket 2 is connected at 0.2 MPas of the pressure.
[0364] The wind-up roll 5b is installed in the further lower stream
of the inert gas blanket 2 in the substrate transport direction
(the direction of the arrow) and can wind the PP nonwoven fabric 6
on which the image has been formed.
[0365] Here, in the present Example, an example in which the
nonwoven fabric on which the image is formed was winded was shown,
however, process treatment such as cutting into the desired shape,
or the like may be conducted without winding after passing through
the inert gas blanket 2, as described above.
[0366] In addition, in the inkjet head, QE10 (manufactured by
FUJIFILM Dimatix, Inc., 100 npi, capable of discharging 10 pl of
ink droplets) and QE80 (manufactured by FUJIFILM Dimatix, Inc., 100
npi, capable of discharging 80 pl of ink droplets) in addition to
QE 30 described above were exchanged and used in accordance with an
experiment standard.
Example 1
[0367] The cyan ink C-1, the magenta ink M-1, the yellow ink Y-1
and the black ink K-1 which were prepared as above were used, and
the image was formed under the following conditions by using the
inkjet recording device described above. As the image, a solid
image of 100% four colors (the ratios of each color are C: 20%, M:
20%, Y: 20% and K. 40%), a solid image of 100% magenta color and a
solid image of 100% yellow color were formed.
[0368] <Conditions>
(i) Adjust the oxygen partial pressure to the value shown in Table
2 described below by flowing nitrogen gas at a flow rate from 2
L/min to 10 L/min so that N.sub.2 gas concentration in the inert
gas blanket 2 is in a range from 90% to 99% (ii) Transport speed of
the nonwoven fabric: 200 m/min (iii) Distance between the inkjet
head and the nonwoven fabric (the stopped state standard): 10 mm
(iv) Amount of ink droplets: 70 pl (v) Resolution of the image: 200
dpi.times.200 dpi (vi) Pinning light source: light up when
drawing
[0369] Furthermore, in addition to the cyan ink C-1, the magenta
ink M-1, the yellow ink Y-1 and the black ink K-1, the cyan inks
C-2, C-3, C-4, the magenta inks M-2, M-3, M-4, the yellow inks Y-2,
Y-3, Y-4, and the black inks K-2, K-3, K-4 were respectively
prepared in the same way as the cyan ink C-1, the magenta ink M-1,
the yellow ink Y-1 and the black ink K-1 and the images were formed
using these in the same way, except changing SR341 to FA512A
described below which is a monofunctional monomer so that the
content ratio (100% by mass) of the polymerizable compound of
bifunction or more to the total polymerizable compound (monomer)
becomes 50%, 70% or 80% (mass ratio) in each ink.
[0370] FA512A Dicyclopentadienyl oxyethylacrylate
((Dicyclopentenyloxyethyl acrylate), manufactured by Hitachi
Chemical Co., Ltd.)
##STR00020##
[0371] (Evaluation 1)
[0372] As to the images which were formed using the cyan inks C-1
to C-4, the magenta inks M-1 to M-4, the yellow inks Y-1 to Y-4,
and the black inks K-1 to K-4 described above, the following
evaluations were conducted. The evaluation results are shown in
Table 2 described below.
[0373] (1) Quantitative Determination of Residual Monomer
[0374] The solid image of 100% four colors was immersed into a
mixed solution of tetrahydrofuran and methanol (THF:MeOH=1:1) and a
uncured residual monomer was extracted. Afterward, the quantity of
the uncured residual monomer contained in the extraction liquid was
determined by liquid chromatography Prominence HPLC system
(manufactured by Shimadzu Corporation, column: TSK-gel ODS 100Z
(446 mm.times.150 mm) is installed) and the amount of the residual
monomer (% by mass) was calculated by the following expression. The
amount of the uncured residual monomer is shown in Table 2
described below (as a monomer, an alcohol body which is not
acrylated is also included.). Here, as to the content of the
residual monomer, the targeted value was set to 0.1% or less. the
amount of the residual monomer (% by mass)=(the amount of the
uncured residual monomer/the total amount of the
monomer).times.100
[0375] (2) Odor Properties
[0376] As to odor of the solid image of 100% four colors, the
sensory evaluation was conducted according to the following
evaluation criteria. Specifically, the solid image was connoted in
a 30 cm.times.30 cm of plastic bag with a zipper and left for 24
hours. Afterward, the zipper was released and the evaluation of the
odor was conducted. As to the evaluation, the average value which
averages out the evaluation values of 10 people (however, an
integer which the first figure of decimal position of the average
value is rounded off when the average value includes a decimal
point) was employed. If the result falls under 1 or 2 of the
following evaluation criteria, then there is no issue with the
practical use.
[0377] <Evaluation Criteria>
1: There is no odor. 2: There is only slight odor but it is barely
noticed. 3: There is a certain level of odor but it is not
unpleasant level. 4: There is strong odor.
[0378] (3) Head Rubbing
[0379] As described before, the number of contacts with the head
was confirmed when the transport speed was set to 200 m/min and the
solid image of 100% four colors was formed, and the evaluation was
conducted according to the following evaluation criteria. If the
result falls under 1 or 2 of the following evaluation criteria,
then there is no issue with the practical use.
[0380] <Evaluation Criteria>
1: There is no contact with the head. 2: There is a contact with
the head once in a case of transporting for 200 m. 3: The number of
contacts with the head which is generated in a case of transporting
for 200 m is less than 10. 4: The number of contacts with the head
which is generated in a case of transporting for 200 m is 10 or
more.
TABLE-US-00002 TABLE 2 Ink Content ratio of Content polymerizable
ratio of Oxygen compound of residual partial bifunction or monomer
pressure more [mass Odor [mass [MPa] Kind ratio] properties ratio]
Rubbing Notes 10 .times. 10.sup.-2 C-2/M-2/Y-2/K-2 50% 4 5% 4
Comparative Example 10 .times. 10.sup.-2 C-3/M-3/Y-3/K-3 70% 4 3% 4
Comparative Example 10 .times. 10.sup.-2 C-4/M-4/Y-4/K-4 80% 4 2% 4
Comparative Example 10 .times. 10.sup.-2 C-1/M-1/Y-1/K-1 100% 4 1%
4 Comparative Example 2 .times. 10.sup.-2 C-2/M-2/Y-2/K-2 50% 4 4%
4 Comparative Example 2 .times. 10.sup.-2 C-3/M-3/Y-3/K-3 70% 4 2%
4 Comparative Example 2 .times. 10.sup.-2 C-4/M-4/Y-4/K-4 80% 4 1%
4 Comparative Example 2 .times. 10.sup.-2 C-1/M-1/Y-1/K-1 100% 4
0.50% 4 Comparative Example 1.5 .times. 10.sup.-2 C-2/M-2/Y-2/K-2
50% 4 3% 4 Comparative Example 1.5 .times. 10.sup.-2
C-3/M-3/Y-3/K-3 70% 3 0.20% 3 Comparative Example 1.5 .times.
10.sup.-2 C-4/M-4/Y-4/K-4 80% 2 0.01% 2 Present invention 1.5
.times. 10.sup.-2 C-1/M-1/Y-1/K-1 100% 1 Not 1 Present detected
invention 1 .times. 10.sup.-2 C-2/M-2/Y-2/K-2 50% 4 2% 4
Comparative Example 1 .times. 10.sup.-2 C-3/M-3/Y-3/K-3 70% 3 1% 3
Comparative Example 1 .times. 10.sup.-2 C-4/M-4/Y-4/K-4 80% 2 0.01%
2 Present invention 1 .times. 10.sup.-2 C-1/M-1/Y-1/K-1 100% 1 Not
1 Present detected invention
[0381] As shown in Table 2, in the present invention, by
polymerizing the predetermined ink under the predetermined oxygen
partial pressure (1.5.times.10.sup.-2 MPa or less), the odor
properties, the amount of the residual monomer and the rubfastness
were excellent. In contrast, in Comparative Examples, the odor
properties, the amount of the residual monomer and the rubfastness
were debased.
Example 2
[0382] The cyan ink C-1, the magenta ink M-1, the yellow ink Y-1
and the black ink K-1 which were prepared in Example 1 and the
inkjet recording device were used, the amount of ink droplets of
the ink which was discharged and the distance between the inkjet
head and the nonwoven fabric (the stopped state standard; =the slow
distance) were changed as shown in Table 3 described below, and the
image was formed under the following conditions. As the images, the
solid image of 100% four colors (the ratios of each color are C:
20%, M: 20%, Y: 20% and K: 40%) and the solid image of 100% magenta
color were formed in the same way as Example 1.
[0383] <Conditions>
(i) Amount of ink droplets and the inkjet head When the amount of
ink droplets=10 pl, the inkjet head QE-10 is used. When the amount
of ink droplets=20 pl, the inkjet head QE-10 is used and the ink is
discharged by a multidrop method. When the amount of ink
droplets=30 pl, the inkjet head QE-30 is used. When the amount of
ink droplets=80 pl, the inkjet head QE-80 is used. (ii) Slow
distance: adjust by vertically moving the fixed position of the
head (iii) Transport speed of the nonwoven fabric: 200 m/min (iv)
Oxygen partial pressure: adjust to 1.times.10.sup.-2 MPa (v)
Resolution of the image: 200 dpi.times.200 dpi (vi) Pinning light
source: light up when drawing
[0384] (Evaluation 2)
[0385] As to the images formed using the cyan ink C-1, the magenta
ink M-1, the yellow ink Y-1 and the black ink K-1 described above,
the following evaluations were conducted. The evaluation results
are shown in Table 3 described below.
[0386] Here, the evaluation of head rubbing was conducted in the
same way as Example 1.
[0387] (4) Line Quality
[0388] In a black image, the quality of lines in the array
direction of the nozzle of the head and lines in the vertical
direction thereof was evaluated according to the following
evaluation criteria. Specifically, the evaluation was conducted by
measuring how many portions were found broken in 2.54 cm (1 inch)
of line. If the result falls under 1 or 2 of the following
evaluation criteria, then there is no issue with the practical
use.
[0389] <Evaluation Criteria>
1: The portions which are broken are not found and the line quality
is excellent. 2: The portions which are broken are found but are
less than 5 portions. 3: 5 or more portions which are broken are
found. 4: The lines cannot be formed.
TABLE-US-00003 TABLE 3 Amount of ink droplets Slow Line Head [pl]
distance quality rubbing Notes 10 1 mm 1 4 Comparative Example 10 4
mm 3 3 Comparative Example 10 5 mm 4 2 Comparative Example 10 10 mm
4 1 Comparative Example 10 20 mm 4 1 Comparative Example 10 25 mm 4
1 Comparative Example 20 5 mm 4 1 Comparative Example 30 1 mm 1 4
Comparative Example 30 4 mm 1 3 Comparative Example 30 5 mm 2 2
Present invention 30 10 mm 2 1 Present invention 30 20 mm 2 1
Present invention 30 25 mm 4 1 Comparative Example 80 1 mm 1 4
Comparative Example 80 4 mm 1 3 Comparative Example 80 5 mm 1 2
Present invention 80 10 mm 1 1 Present invention 80 20 mm 2 1
Present invention 80 25 mm 3 1 Comparative Example
[0390] As shown in Table 3, in the present invention which
satisfies a predetermined amount of ink droplets and the slow
distance, it was possible to form excellent lines without occurring
head rubbing. In contrast, in Comparative Examples, the line
quality significantly deteriorated. In Comparative Examples in
which the slow distance was set to less than 5 mm, head rubbing
occurred, and in Comparative Examples in which the slow distance
was set to over 20 mm, even a predetermined amount of ink droplets
was adjusted, the line quality significantly deteriorated.
Example 3
[0391] The cyan ink C-1, the magenta ink M-1, the yellow ink Y-1
and the black ink K-1 which were prepared in Example 1 and the
inkjet recording device were used, and the images were formed at a
resolution (image density) shown in Table 4 described below by
increasing or decreasing the number of the used heads of each
color. However, 50 dpi (dot per inch) of the image was alternately
drawn by half of the nozzles using one inkjet head. As the images,
the solid image of 100% four colors (the ratios of each color are
C: 20%, M: 20%, Y: 20% and K: 40%) and the solid image of 100%
magenta color were formed in the same way as Example 1.
[0392] <Conditions>
(i) Transport speed of the nonwoven fabric: 200 m/min (ii) Oxygen
partial pressure: adjust to 1.times.10.sup.-2 MPa (iii) Distance
between the inkjet head and the nonwoven fabric (the stopped state
standard; the slow distance): 10 mm (vi) Amount of ink droplets: 80
pl (v) Pinning light source: light up when drawing
[0393] (Evaluation 3)
[0394] As to the images formed using the cyan ink C-1, the magenta
ink M-1, the yellow ink Y-1 and the black ink K-1 described above,
the following evaluations were conducted. The evaluation results
are shown in Table 4 described below.
[0395] Here, the evaluation of the periodicity and the amount of
the residual monomer was conducted in the same way as Example
1.
[0396] (5) Rubfastness
[0397] The solid image of 100% four colors was rubbed with cotton
which was moist with water, and the rubfastness was evaluated by
measuring the difference of the solid image concentration before
and after the abrasion test by Gretag Macbeth Spectro Eye
manufactured by Gretag Macbeth Co., Ltd. The lower value indicates
that the color does not fade and the rubfastness is excellent. If
the result falls under 1 or 2 of the following evaluation criteria,
then there is no issue with the practical use.
[0398] <Evaluation Criteria>
1: The color does not fade at all and the difference of the
measured value of the image concentration before and after the
abrasion test is less than 0.05. 2: The color is slightly migrated
to cotton which was rubbed and the difference of the measured value
of the image concentration before and after the abrasion test is
0.05 or more and less than 0.2. 3: The color is largely migrated to
cotton which was rubbed and the difference of the measured value of
the image concentration before and after the abrasion test is 0.2
or more and less than 0.4. 4: The color fading of the image is
visually recognized and the difference of the measured value of the
image concentration before and after the abrasion test is 0.4 or
more.
[0399] (6) Void
[0400] As to the solid image of 100% magenta color, the presence or
absence of the occurrence of a void was visually observed and the
evaluation was conducted according to the following evaluation
criteria. If the result falls under 1 or 2 of the following
evaluation criteria, then there is no issue with the practical
use.
[0401] <Evaluation Criteria>
1: The void can not be confirmed by sight. 2: The void can be
slightly confirmed by sight. 3: The void can be confirmed by
sight.
TABLE-US-00004 TABLE 4 Amount of Odor residual Rubfast- Image
density properties monomer ness Void Notes 600 dpi .times. 600 dpi
2 0.1% 2 1 Present invention 400 dpi .times. 400 dpi 2 0.01% 2 1
Present invention 300 dpi .times. 300 dpi 2 0.01% 1 1 Present
invention 200 dpi .times. 200 dpi 1 Not 1 1 Present detected
invention 100 dpi .times. 100 dpi 1 Not 1 2 Present detected
invention 50 dpi .times. 50 dpi 1 Not 1 2 Present detected
invention
[0402] As shown in Table 4, excellent odor properties, the amount
of the residual monomer and the rubfastness were exhibited. Among
those, in a case where the image was formed at a resolution of 100
dpi to 400 dpi, the drying load was further suppressed and better
odor properties, the amount of the residual monomer and the
rubfastness were obtained. The trend was seen in that the
resolution of the image became too high, the deterioration in the
odor properties, the amount of the residual monomer and the
rubfastness easily appeared, and adversely, the resolution of the
image became too low, the void of the image easily was
observed.
Example 4
[0403] In the preparation of the cyan ink C-1, the magenta ink M-1,
the yellow ink Y-1 and the black K-1 in Example 1, the cyan ink
C-5, the magenta ink M-5, the yellow ink Y-5 and the black ink K-5,
or the cyan ink C-6, the magenta ink M-6, the yellow ink Y-6 and
the black ink K-6 were prepared in the same way as Example 1 except
changing Speedcure 7010 which is a sensitizer to the same quantity
of SR341 (3-methyl-1,5-pentanediol diacrylate; polymerizable
monomer) or the same quantity of Speedcure ITX
(isopropylthioxanthone, manufactured by LAMB SON Ltd., the
molecular weight: 254) and the images were formed under the
following conditions.
[0404] Furthermore, in the preparation of the cyan ink C-1, the
magenta ink M-1, the yellow ink Y-1 and the black K-1 in Example 1,
the cyan ink C-7, the magenta ink M-7, the yellow ink Y-7 and the
black ink K-7 were prepared in the same way as Example 1 except
changing Speedcure 7010 which is a sensitizer to the same quantity
of the compound I-F described below (n=20, the molecular weight:
1934; the sensitizer represented by the general formula (2)), and
the images were formed under the following conditions.
[0405] In addition, in the preparation of the cyan ink C-1, the
magenta ink M-1, the yellow ink Y-1 and the black K-1 in Example 1,
the cyan ink C-8, the magenta ink M-8, the yellow ink Y-8 and the
black ink K-8 were prepared in the same way as Example 1 except
changing Speedcure 7010 which is a sensitizer to the same quantity
of the compound I-I described below (k=20, l=20, m=20, the
molecular weight: 4328; the sensitizer represented by the general
formula (2)), and the images were formed under the following
conditions.
##STR00021##
[0406] Here, as the images, the solid image of 100% four colors
(The ratios of each color are C: 20%, M: 20%, Y. 20% and K: 40%)
and the solid image of 100% magenta color were formed in the same
way as Example 1.
[0407] <Conditions>
(i) Transport speed of the nonwoven fabric: 200 m/min (ii) Oxygen
partial pressure: adjust to 1.times.10.sup.-2 MPa (iii) Distance
between the inkjet head and the nonwoven fabric (the stopped state
criteria; the slow distance): 10 mm (vi) Amount of ink droplets: 80
pl (v) Resolution of the image: 200 dpi.times.200 dpi (vi) Pinning
light source: light up when drawing
[0408] (Evaluation 4)
[0409] As to the images formed using the cyan inks C-5 to C-8, the
magenta inks M-5 to M-8, the yellow inks Y-5 to Y-8 and the black
inks K-5 to K-8 described above, the following evaluations were
conducted. The evaluation results are shown in Table 5 described
below. Here, the evaluation of the odor properties, the amount of
the residual monomer and the rubfastness was conducted in the same
way as Example 1.
TABLE-US-00005 TABLE 5 Amount of Odor residual Rub- proper- monomer
fast- Kind of ink ties [mass ratio] ness Other Notes C-5/M-5/ 4 5%
4 -- Comparative Y-5/K-5 Example C-6/M-6/ 1 Not 1 The Comparative
Y-6/K-6 detected overflow of Example ITX is present. C-1/M-1/ 1 Not
1 -- Present Y-1/K-1 detected invention C-7/M-7/ 1 Not 1 -- Present
Y-7/K-7 detected invention C-8/M-8/ 1 Not 1 -- Present Y-8/K-8
detected invention
[0410] As shown in Table 5, in the present invention in which the
sensitizer having high molecular weight was used, the odor
properties, the amount of the residual monomer and the rubfastness
were excellent. In contrast, in Comparative Examples in which the
sensitizer was not added, the odor properties, the amount of the
residual monomer and rubfastness deteriorated. In addition, in
Comparative Examples in which the sensitizer having low molecular
weight was used, the outflow of sensitizer was observed while the
residual monomer was not detected.
Example 5
[0411] The cyan ink C-1, the magenta ink M-1, the yellow ink Y-1
and the black ink K-1 which were prepared in Example 1 and the
inkjet recording device were used, and the image was formed by
lighting or not lighting the pinning light source. As the images,
the solid image of 100% four colors (the ratios of each color are
C: 20%, M: 20%, Y: 20% and K: 40%) and the solid image of 100%
magenta color were formed in the same way as Example 1.
[0412] <Conditions>
(i) Transport speed of the nonwoven fabric: 200 m/min (ii) Oxygen
partial pressure: adjust to 1.times.10.sup.-2 MPa (iii) Distance
between the inkjet head and the nonwoven fabric (the stopped state
criteria; the slow distance): 10 mm (vi) Amount of ink droplets: 80
pl (v) Resolution of the image: 200 dpi.times.200 dpi
[0413] (Evaluation 5)
[0414] As to the images formed using the cyan ink C-1, the magenta
ink M-1, the yellow ink Y-1 and the black ink K-1 which were
prepared in Example 1 and the inkjet recording device, the color
bleeding was evaluated by the following method. The evaluation
results are shown in Table 6 described below.
[0415] (7) Color Bleeding
[0416] The solid image of 100% black color was formed right beside
the solid image of 100% yellow color, the presence or absence of
the occurrence of color bleeding is visually observed, and the
evaluation was conducted according to the following evaluation
criteria. If the result falls under 1 or 2 of the following
evaluation criteria, then there is no issue with the practical
use.
[0417] <Evaluation Criteria>
1: Black is not mixed in the yellow drawing part at all. 2: A
slight amount of black is mixed in the yellow drawing part. 3: A
large amount of black is mixed in the yellow drawing part.
TABLE-US-00006 TABLE 6 Pinning Color light source bleeding Notes
Lighted 1 Present invention Not 2 Present lighted invention
[0418] As shown in Table 6, in a case where the pinning exposure
was conducted, the color bleeding in the image did not occur at
all. In contrast, in a case where the pinning exposure was not
conducted, the color bleeding slightly occurred.
* * * * *